Albuminuria and renal injury—beware of proteins bearing gifts

Abstract
Over the last two decades a shift in paradigm has taken place regarding the role of proteinuria in the progression of renal disease. Across a wide spectrum of glomerular and non‐glomerular diseases (especially those characterized by tubulointerstitial fibrosis), the degree of proteinuria has been shown to correlate with the risk of progression to end‐stage renal disease [ 1]. Initially, proteinuria was thought simply to be a marker of the severity of glomerular injury. Recent evidence, however, suggests that proteinuria, and particularly albuminuria, may itself promote tubular injury, with interstitial inflammation and eventual fibrosis [ 2, 3].