Soluble Urokinase Receptor as a Biomarker in Kidney Disease

Abstract

Urokinase receptor (uPAR), a glycosylphosphatidylinositol (GPI)-anchored protein, engages in multiple protein-protein interactions and various biological functions. Its soluble form, soluble uPAR (suPAR), has been linked to various diseases and conditions including focal segmental glomerulosclerosis (FSGS). It has been long speculated that a circulating permeability factor should be implicated in the pathogenesis of the disease because a substantial portion of the patients experience recurrence shortly after renal transplantation. In 2011, Reiser and colleagues suggested that suPAR might be not only a potential pathogenic permeability factor but also a diagnostic biomarker. Following this report, renal researchers worldwide have analyzed the validity of suPAR as a diagnostic biomarker for primary FSGS and posttransplant FSGS. Furthermore, the utility of suPAR as a biomarker in other renal diseases including diabetic nephropathy and immunoglobulin A (IgA) nephrosis has been also suggested.