The role of the glomerular epithelial cell in the maintenance of the glomerular filtration barrier.

Glomerular epithelial cells contribute significantly to the hydraulic and macromolecular permeability properties of the glomerulus. Because of their location as the terminal element in the filtration barrier and their elaborate cytoskeleton, they are likely to participate in the regulation of filtration. In disease, alterations of the glomerular epithelial cells may lead to simplification and retraction of foot processes, resulting in a decreased density of slit diaphragms and decreased by hydraulic conductivity. In addition, denudation of epithelial cells from the basement membrane results in increased macromolecular permeability at those sites and accounts for much of the proteinuria in a variety of types of renal disease.