A–C: immunoblots showing decreased vascular endothelial (VE)-cadherin protein in lungs of Eln+/− compared with Eln+/+ pups (A), quantitative assessment of pulmonary arterioles (20–100 μm diameter) (B) and smaller microvessels (<20 μm diameter) (C), predominantly capillaries (<10 μm diameter), showing less capillary surface density/100 alveoli in lungs of Eln+/− compared with Eln+/+ pups. Summary data, means and SD; n = 6/group; *significant difference, P < 0.05. D: images of Eln+/+ and Eln+/− lung sections (×400; scale bars 20 μm) stained with CD-31 antibody (brown), denoting discernible pulmonary capillaries (arrows). E: Eln+/+ and Eln+/− lung sections stained with α-smooth muscle (SM) actin antibody showed less medial smooth muscle thickness, expressed as a percent of vessel diameter, in pulmonary arterioles (<40 and 40–80 μm diameter) of Eln+/− compared with Eln+/+ newborn mice. Summary data, means and SD; n = 135 for Eln+/+ <40-μm arterioles, n = 17 for Eln+/+ 40- to 80-μm arterioles, n = 136 for Eln+/− <40-μm arterioles, n = 44 for Eln+/− 40- to 80-μm arterioles; *significant difference, P < 0.05.