Fig. 2: CCM lesions bulged from the capillary/post-capillary venules with blinding ends.

a Tamoxifen feeding protocols. WT (Pdcd10^fl/fl) and Pdcd10^BECKO (Mfsd2aCreER^T2; Pdcd10^fl/fl) pups were fed tamoxifen at different times to induce Ccm3 deletion at P1, P5, P10, and P21, respectively. Lesion phenotypes were analyzed at P60. b CCM lesions visualized by whole-brain imaging. c Live confocal microscopy of vascular malformations after injection of Evans blue dye (EBD in cyan color). Arrowheads and arrows indicate normal capillary and cavern, respectively. Asterisks indicate large lesions. A; artery/arterioles; V: vein/venules. d–j Characterization of vascular structure and perfusion. CCM lesions and perfusion in 2-month-old WT (Mfsd2aCreER^T2:mT/mG) and Pdcd10^BECKO:mT/mG mice were visualized by confocal microscopy after injection with EBD. Blue: EBD; green: mG, primarily expressed in veins/venules/capillaries/arterioles; red: mT, all blood vessels. d Representative images of normal vessels in WT mice and mild to moderate lesions in Pdcd10^BECKO mice are shown, with higher magnifications without EBD color at the lower panels. Arrowheads indicate normal capillaries/post-capillary venules in WT and Pdcd10^BECKO mice, whereas arrows indicate non-perfused newly formed sprouts in Pdcd10^BECKO mice. e The number of lesions (caverns-like structure/vascular area) are quantified. n = 4. f, g Total vascular area (mG) and EBD-perfused area are quantified. h Non-perfused (mG⁺/EBD⁻) area is quantified. i Comparison of vein junctions in WT (arrowhead) and Pdcd10^BECKO (arrow). Quantifications of vein diameters (j). n = 3. k–m Two-month-old WT and Pdcd10^BECKO mice were perfused with a Texas Red intravenous (IV) dye and NeuroTrace (pericytes) followed by confocal microscopy. k Representative images of normal vessels in WT mice and mild to moderate lesions in Pdcd10^BECKO mice are shown. l, m Pericyte-free caverns and pericyte density (number/vascular area) were quantified. n = 4. Arrowheads indicate normal pericyte processes in WT mice, whereas arrows indicate pericytes with shortened processes in Pdcd10^BECKO mice. Asterisks indicate CCM lesions in Pdcd10^BECKO mice. Data are means ± SEM. P values are indicated, one-way ANOVA followed by Sidak’s multiple comparisons test (e); one-way ANOVA followed by Tukey’s multiple comparisons test (f, g, h, j, l, m). Scale bar: 2 mm (b); 50 μm (c); 2 μm (d, k). Source data are provided as a Source data file.