Glomerular endothelium: A porous sieve and formidable barrier

The glomerular capillary endothelium is highly specialized to support the selective filtration of massive volumes of plasma. Filtration is driven by Starling forces acting across the glomerular capillary wall, and depends on its large surface area and extremely high water permeability. Glomerular endothelial cells are extremely flat and perforated by dense arrays of trans-cellular pores, the fenestrae. This phenotype is critical for the high glomerular water permeability and depends on podocyte-derived VEGF, as well as TGF-beta. Endothelial cell-derived PDGFB, in turn, is necessar