PERMSELECTIVITY OF THE GLOMERULAR-FILTRAT ION BARRIER IN HUMANS

Glomerular ultrafiltration of macromolecules is a biophysical process sharing both a diffusive and a convective component, governed by glome rular hemodynamics, through a composite structure, the glomerular filt ration barrier. Studies of the fractional clearance of macromolecules have showed that transcapillary filtration of macromolecules is hinder ed by size, electrostatic charge and to a lesser degree by spatial con formation. Several modelizations of ultrafiltration have been developp ed to quantify the respective role of glomerular hemodynamic and/or me mbrane structural alternations as found in glomerular diseases.