Soluble urokinase-type plasminogen activator receptor (suPAR) is a risk indicator for eGFR loss in kidney transplant recipients.

The prognostic significance of suPAR in various kidney diseases has recently been demonstrated. Its role in transplantation-specific outcomes is still largely unknown. Therefore, we prospectively investigated the prognostic relevance of suPAR in patients before and one year after kidney transplantation (KTx). We included 100 patients who had received a kidney transplantation between 2013 and 2015. The plasma concentration of suPAR was measured by ELISA assay. In recipients of living donations (LD), pre-transplant suPAR levels were significantly lower than those of recipients of deceased donations (DD). After KTx, suPAR levels significantly declined in LD and DD recipients, without a detectable difference between both groups any more. Higher suPAR levels in recipients one year after KTx were associated with a more severe eGFR loss in the following three years in multivariable cox-regression (n = 82, p = 0.021). suPAR-levels above 6212 pg/ml one year after KTx are associated with eGFR loss > 30%, which occurred almost twice as fast as in patients with suPAR ≤ 6212 pg/ml (p < 0.001). Hence, suPAR level at one year mark might be a risk indicator of increased eGFR loss.

Prognostic Value of Growth Differentiation Factor 15 in Kidney Donors and Recipients.

Growth differentiation factor-15 (GDF15) is associated with inflammatory conditions, chronic kidney disease, cardiovascular disease and mortality. There is very limited data on GDF15 after kidney donation and transplantation. We analyzed serum samples of patients who donated a kidney (54 living donors) or who underwent kidney transplantation (104 recipients) at the University Hospital of Münster (Germany) between 2013 and 2015, for GDF15 levels immediately prior and one year after surgery. GDF15 levels were significantly elevated in end-stage renal disease patients compared to healthy individuals (2844 (IQR 2087, 3361) pg/ml vs. 384 (IQR 307, 487) pg/ml, p < 0.001). GDF15 was strongly associated with the dialysis vintage. While kidney transplantation led to a significant decrease of GDF15 (913 (IQR 674, 1453) pg/ml, p < 0.001), kidney donation caused a moderate increase of GDF15 (510 (IQR 420, 626), p < 0.001) one year after surgery. GDF15 levels remained significantly higher in recipients and kidney donors than in healthy controls (735 (IQR 536, 1202) pg/ml vs. 384 (IQR 307, 487) pg/ml, p < 0.001). GDF15 is increased in patients with kidney disease and is associated with dialysis vintage. Given its decrease after transplantation and its increase after uni-nephrectomy, GDF15 might be a marker of kidney function. However, since it correlates only to the eGFR in transplanted patients it may indicate chronic kidney disease.