Histologic and cardiac alterations after conditional inactivation of PHD2. (A,B) Gross appearance of abdomen in PHD2^+/+;Cre-ER (A) and PHD2 flox/flox;Cre-ER (B) mice treated with tamoxifen at E17.5 and at 3 weeks of age. Note large retroperitoneal hematoma (asterisk) in PHD2 flox/flox;Cre-ER mouse (B). (C-L) Hematoxylin and eosin staining of PHD2^+/+;Cre-ER (C,E,G,I,K) and PHD2 flox/flox;Cre-ER (D,F,H,J,L) treated with tamoxifen as in panels A and B. Sections are from spine (C,D), liver (E,F), kidney (G,H), lung (I,J), and heart (K,L). Note large retroperitoneal hematoma (arrowheads), severely dilated inferior vena cava (IVC; see also Figure S3), as well as evidence of hemorrhage in spinal canal (arrows). SC indicates spinal cord; V, vertebral body. *Aorta.