Endocardial Vegfr1 is not essential for late coronary development, but required for normal ventricular wall development.

A-D, Images of wholemount Pecam1 stained E14.5 hearts showing comparable coronary vasculatures (arrows indicating individual vessels) between the control and R1 CKO hearts. E-H, Images of Pecam1 stained frontal sections of E14.5 hearts showing comparable coronary vasculatures between the control and R1 CKO hearts (arrows indicating individual vessels). Note that the CKO hearts have a thin compact myocardium. Scale bar = 50 µm. I, Quantitative analysis showing comparable numbers of coronary endothelial cells between E14.5 control and R1 CKO hearts. n = 3 individual hearts, 5 comparable sections per heart, error bars = SD. J, Quantitative analysis showing that the thickness of the compact myocardium is significantly reduced in the R1 CKO embryos compared to the control embryo. n = 3 individual hearts; 5 comparable sections per heart. *p