Expression of Urokinase-type Plasminogen Activator Receptor and its Soluble Form in Type 2 Diabetic Kidney Disease.

BACKGROUND

Urokinase-type plasminogen activator receptor (uPAR) and its soluble form (suPAR) are new injury biomarkers that have been recently suggested to play a vital role in renal diseases.

AIM AND METHODS

We evaluated the expression of uPAR and the serum concentration of suPAR in type 2 diabetes (TDM) patients with diabetic kidney disease (DKD) to determine the role of this molecule as a biomarker in DKD. The uPAR immunohistochemical staining was performed in biopsy-confirmed DKD renal tissues. Meanwhile, the serum suPAR, Interleukin-18 (IL-18) and C-reactive protein (CRP) levels of 70 diabetic patients with or without DKD and 15 healthy controls were measured.

RESULTS

The uPAR expression in DKD patients was significantly increased compared to that in healthy controls and was widely colocalized with the podocyte marker WT1. Meanwhile, serum suPAR and IL-18 levels gradually increased as DKD progressed to the advanced stage. Moreover, serum suPAR and IL-18 levels were negatively correlated with eGFR (ρ = ‒0.734, ρ = ‒0.462, p <0.01) and positively correlated with the urine protein to creatinine ratio (UP/CR) (ρ = 0.730, ρ = 0.440, p <0.01). The suPAR AUC performed better than the IL-18 AUC for the diagnosis of proteinuria (0.845 vs. 0.753, p <0.01) and the decline of renal function (0.895 vs. 0.796, p <0.01).

CONCLUSIONS

The uPAR expressed in the renal tissues of DKD patients. The soluble form of uPAR, suPAR, can be detected in the serum of DKD patients and has a better diagnostic efficiency in the diagnosis of proteinuria and renal dysfunction in patients with TDM than that of IL-18.