3D reconstruction of retinal vasculature in 3-week-old WT, Vldlr^-/-, Lrp5^-/- and DKO mice with the Sca1-GFP transgene.

The 3D images were constructed from Z-stack images of GFP-positive ECs, starting from the retinal surface (GCL) through the OPL. The upper panels show a top view of 3D images while the lower panels show a 90 degree–rotated side view of the upper 3D images. The top-view panel (the upper left) reveals wild-type retinal vasculature consisting of large vessels, small vessels and capillaries while the side-view panel (the lower left) shows a typical interconnected 3-layer of retinal vasculature, corresponding to enriched vessels in the GCL (upper), IPL (middle) and OPL (lower), in the wild-type retina. Compared to a clear 3-layer retinal vascular network in the WT control, the Vldlr^-/- retina shows abnormal vessel growth originated from the OPL vessels (white arrowheads). The Lrp5^-/- and DKO retinas display very similar phenotypes, such as incomplete retinal vasculature with only the surface vessel network and the formation of EC clusters in the IPL (white arrows).