What is the pathophysiology of proteinuria?

Updated: Mar 25, 2020
  • Author: Beje Thomas, MD; Chief Editor: Vecihi Batuman, MD, FASN  more...
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Answer

Currently, the development of proteinuria is thought to involve dysfunction of the glomerular filtration barrier, tubular dysfunction, or both. 

The glomerular filration barrier seperates the kidney vasculature from the urinary space.  One of the barrier's primary purposes is to prevent the passage of plasma proteins notably albumin. The small amount of albumin and non-albumin protein that is filtered is reabsorbed in the proximal convoluted tubule (PCT).

The three components of the glomerular filtration barrier are the podocytes (epithelial cells), the fenestrated endothelial cells, and the glomerular basement membrane (GBM). Proteinuria is prevented by the negative charge and size selectivity of the glomerular filtration barrier. Crosstalk among podocytes, mesangium, and endothelium maintains the normal filtration barrier. As all three are interlinked, damage to any one of them affects the functioning of the others.


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