Figure 1. Apln-CreER labels reactivated endothelium in infarcted myocardium.

(a) Schematic figure showing the strategy for ligation of the LAD coronary artery and genetic labelling of Apln⁺ cells by tamoxifen treatment (Tam.) in Apln-CreER;Rosa26^RFP/+ adult mice. (b) Whole mount view of Apln-CreER;Rosa26^RFP/+ hearts 14 days after MI or sham. (c,d) Sections of MI or sham hearts stained with RFP, PECAM and 4',6-diamidino-2-phenylindole (DAPI). Tamoxifen was administered 1 day after MI or sham. (e,f) RFP⁺ vascular ECs (white arrowheads) in infarct, border or remote zone of MI or sham heart. Green arrowheads denote endocardium; red arrowheads indicate non-vascular RFP⁺ cells. (g) Quantification of RFP⁺ vascular ECs. Student’s t-test was used to analyse differences and values are shown as means±s.e.m.; *P<0.05, NS, not significant; n=5 for MI, 3 for sham. (h) Staining of ESR for detection of Apln expression in MI or sham hearts 2 days after MI. LV, left ventricle; RV, right ventricle; VS, ventricular septum. Scale bars, 1 mm (b–d); 100 μm (e,f,h).