Figure 2.

Morphological changes of the glomerular filtration barrier and selectivity of proteinuria. (a) A schematic illustration. (b) A micrograph of a glomerulus in a paraffin section obtained using a low-vacuum scanning electron microscope (LVSEM) in each group of proteinuria selectivity. (c) A micrograph of the glomerular capillary wall obtained using a transmission electron microscope (TEM) in each group of proteinuria selectivity. Selective albuminuria is usually found in patients with minimal change nephrotic syndrome, nonselective proteinuria without hematuria associated with podocyte detachment (yellow arrows) is found in patients with membranous nephropathy, focal segmental glomerulosclerosis, and diabetic nephropathy, and nonselective proteinuria with hematuria associated with GBM rupture/hole (red arrowheads) is found in patients with IgA nephropathy, ANCA-related glomerulonephritis, poststreptococcal acute glomerulonephritis, and membranoproliferative glomerulonephritis. P: podocyte; E: glomerular endothelium; C: glomerular capillary; M: mesangium; RBC: red blood cell. Scale bars indicate 2 μm on the LVSEM micrograph and 500 nm on the TEM micrograph.