F8TKO mice show defenestrated vascularized LSEC with decreased permeability. (A) Liver intravital imaging of control and F8^TKO liver at baseline and 15 days post–AAV8-GFP administration injected with TXR-dextran and AF488-anti-CD31. (B) SEM images show LSEC fenestrae are significantly less in a representative F8^TKO mouse as compared with a control mouse. (C) SEM images show LSEC fenestrae are significantly less in a representative B6; 129S-F8tm1Kaz/J mouse as compared with a control mouse. (D) Quantification of pore grouping and total number of fenestrae per field of view in the liver of control B6; 129S-F8tm1Kaz/J and F8^TKO mice. (E) Heatmap consisting of qRT-PCR analysis of endothelial-specific genes (CD31, VEGF, ICAM1, stabilin2, ID1, Gata4, and Ehd3) in control and F8^TKO mice liver. (F) Western blot analysis of VEGF and CD31 in control and F8^TKO mice at baseline. Immunofluorescence for PECAM (G) and LYVE-1 (H) showed an increased accumulation in F8^TKO mouse liver tissue at baseline, which was not seen in age-matched control liver. All control mice used were unaffected littermate heterozygoes mice.