Figure 2.

Electron microscopy. Representative electron micrographs from wt (A–C) and (ko) (D–I) mice at 7–14 weeks of age are shown. Normal glomerular structure (A) including podocyte foot processes, GBM, and endothelial fenestrae (B) are shown in wild-type mice. The circumferential pattern of pericyte investment around an arteriole and a pericyte (arrowhead) adjacent to an erythrocyte-filled peritubular capillary is shown in (C). In lama4−/− mice dilated glomerular capillaries are present (D). Also shown in D (arrowhead) is a small arteriole with pericytes and abundant extracellular matrix. Lama4 null mice had normal regions of glomerular capillary wall with normal appearing GBM, podocyte foot processes and endothelial fenestrae similar to wild-type mice (E). Abnormal areas of GBM were also detected where out-pockets of GBM were associated with foot process effacement (F, asterisks). Although glomerular endothelial cells were abundant, apoptotic endothelial cells were also noted (G, arrowheads). Areas of mesangial interposition with split basement membranes were also seen in lama4−/− mice (H, arrowhead), as well as dilated peritubular capillaries with nearby and distant pericytes (I, arrowhead).