Fig. 4.

Vascularization between the implanted cardiac cell sheet and vascular bed. (a) After perfusion culture of the vascular bed and cardiac cell sheet for 6 days, black ink was perfused via the artery of the vascular bed. Hematoxylin-eosin staining revealed that the tissue had retained its viability and that the cardiac cell sheet was attached to the porcine small intestine. Black ink was occasionally detected within the implanted cardiac cell sheet (arrows). CS: cardiac cell sheet; VB: vascular bed. (b) Immunostaining for CD31 (green: endothelial cells, ECs) and troponin T (red: cardiomyocytes from the cardiac cell sheet) revealed that cardiomyocytes were still present in the cell sheet after 6 days of perfusion culture and that ECs formed tubular structures that resembled microvessels. Perfused black ink was observed inside the microvessels of the cell sheet (arrows). (c) Immunostaining for CD31 (red: all ECs) and green fluorescent protein (GFP)-positive human umbilical vein endothelial cells (green: co-cultured ECs in the cell sheet) demonstrated that ECs originating from the cardiac cell sheet had formed microvessels. Black ink perfused via the vascular bed was detected in a vessel formed by ECs from the cell sheet (arrow).