Soluble urokinase-type plasminogen activator receptor (suPAR) in focal segmental glomerulosclerosis

Focal and segmental glomerulosclerosis (FSGS) is a histopathological entity that identifies a group of glomerular kidney disorders, which manifest by a certain pattern of sclerosis that involves parts of some glomeruli (focal segmental) on light microscopy. In most cases of FSGS, in particular the primary or idiopathic FSGS, the first site of the damage is the podocyte, which marks the beginning of this disease. However, FSGS can be a secondary process to another injury in the glomeruli, giving the definition of secondary FSGS. A large number of pathogenic factors have been identified, which lead to podocyte injury and, thereafter, to FSGS. Several genetic predispositions and mutations have been confirmed, especially in young patients, causing an early onset of primary FSGS. Acquired causes of FSGS constitute a large list of factors that may directly or indirectly injure the podocyte cells. Identifying these factors in the cases of primary or idiopathic FSGS has been the focus of extensive research investigations. For many decades, researchers speculated the presence of circulating factors to be the pathogenic causes of primary FSGS. These factors are thought to be the cause of FSGS recurrence post-kidney transplantation as well. However, not until recently, these factors are being identified. In 2011, soluble urokinase plasminogen activator receptor (suPAR) was suggested to be a circulating factor leading to primary FSGS and post-transplantation FSGS recurrence.