From Proteinuria to Fibrosis: An Update on Pathophysiology and Treatment Options

Abstract

<b><i>Background:</i></b> Proteinuria is a key biomarker in nephrology. It is central to diagnosis and risk assessment and the primary target of many important therapies. Etiologies resulting in pathological proteinuria include congenital and acquired disorders, as well as both glomerular (immune/non-immune mediated) and tubular defects. <b><i>Summary:</i></b> Untreated proteinuria is strongly linked to progressive loss of kidney function and kidney failure. Excess protein reaching the renal tubules is ordinarily resorbed by the tubular epithelium. However, when these mechanisms are overwhelmed, a variety of inflammatory and fibrotic pathways are activated, causing both interstitial fibrosis and glomerulosclerosis. Nevertheless, the specific mechanisms underlying this are complex and remain incompletely understood. Recently, a number of treatments, in addition to angiotensin system blockade, have been shown to effectively slow the progression of proteinuric chronic kidney disease. However, additional therapies are clearly needed. <b><i>Key message:</i></b> This review provides an update on the pathophysiology of proteinuria, the pathways leading to fibrosis, and an overview of current and emerging therapies.