Figure 8.

Serial FIB/SEM images revealed two kinds of leakage pathways for plasma proteins in PAN nephrosis. (A and B) Intercellular pathway shown by FIB/SEM images. This pathway was found between purple and green podocytes as the intercellular spaces/gaps without presence of any junctional apparatus (arrows). (C1, C2, D, E1, and E2) Three types of pseudocyst shown by FIB/SEM images. Pseudocysts were formed within the purple podocyte. Type-1 pseudocyst opened toward the GBM (arrow in C1); type-2 pseudocysts were completely closed (D); type-3 pseudocysts opened to the urinary space via small opening (arrow in E1). The type-1 and type-2 pseudocysts frequently contained amorphous materials, whereas type-3 pseudocysts did not contain any amorphous materials. The openings of type-1 and type-3 pseudocysts are magnified in (C2 and E2), respectively. The serial FIB/SEM images containing (C1, D, and E1) are shown in Supplemental Figures 8–10, respectively. (F) Transcellular pathway shown by a schematic diagram. This pathway is presumably formed by the transition between pseudocystic types in the order of type 1, type 2, and type 3. Asterisks indicate lumen of the pseudocysts; yellow lines indicate the GBM. Scale bars, 500 nm in (A and B); 1 μm in (C1, D, and E1). CL, capillary lumen; US, urinary space.