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 (T2DM) 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 T2DM than that of IL-18.
Keywords: Diabetic kidney disease; Soluble urokinase-type plasminogen activator receptor; Type 2 diabetes mellitus; Urokinase-type plasminogen activator receptor.
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