PDGF-D stabilizes VEGF-E–induced blood vessels. Staining for SMA in skeletal muscle injected with the indicated viral vectors. (A, arrowheads) Note the irregular SMC coating and enlarged vessels an AAV-VEGF-E–injected muscle. When injected with a combination of (B) AAV-VEGF-E and AAV-PDGF-D or (C) AAV-VEGF-E and AAV-PDGF-B, the vessels are still enlarged compared with (D) PBS-injected muscle, but the SMC coating is thick and regular (arrowheads; original magnification, ×100). FITC-dextran–injected mouse ears 1 minute after injection shown for mice injected with the indicated AAV vectors. (E, asterisk) Note that AAV-VEGF-E–induced angiogenic vessels leak the FITC-dextran, but a large part of this leak is halted when AAV-VEGF-E is combined with AAV-PDGF-D or PDGF-B (G, I). Comparison with (H) AAV-PDGF-D, (J) AAV-PDGF-B, and (F) AAV-HSA (original magnification, ×20). Bars represent 250 μm (J) and 20 μm (A-D).