Fig. 1
Analysis of vessel-stabilizing angiopoietin-1 treatment. a Exemplary contrast enhancement curves and corresponding sequential T1-weighted images of angiopoietin-1 treated tumors compared to untreated control tumors. While leaky 4T1 control tumors exhibit a plateau, angiopoietin-1 treated 4T1 tumors show a pronounced washout of the contrast agent. b Exemplary Ktrans and T1 maps post-gadofosveset injection. c Area under the curve (AUC), maximum slope (slopemax), Ktrans and ∆T1 analyses assessing decreased tumor perfusion and permeability after treatment. Each dot represents one animal, with horizontal lines indicating the mean. d Ex vivo analysis of angiopoietin-1 treated tumors compared to control groups. While untreated 4T1 tumors show intratumoral hemorrhage (H&E, arrows), no hemorrhage is observed after angiopoietin-1 treatment, with tumors showing decreasing CD31 expression. Scale bars of immunohistochemical stainings represent 50 µm. Transmission electron micrographs (TEM) show thin endothelial layers with several interruptions (dashed circles) in untreated tumors. Angiopoietin-1 treated tumors demonstrate overall thicker and continuous endothelium with intact basal lamina. e erythrocyte, el endothelial layer, bl basal lamina, cf collagen fibrils. Scale bars of TEM images indicate 1 µm. **p < 0.01, ***p < 0.001, ****p < 0.0001