Figure 2

GFP-positive bone marrow derived cells incorporate into the vessel wall at sites of neointimal formation. Sections from cuffed femoral artery segments from GFP-chimeric animals show incorporation of bone marrow derived cells. TRITC-labeled α-SMA-positive and bone marrow derived GFP-positive cells are shown in separate fluorescence channels (A/D and B/E respectively) and in overlay images (C/F, including DAPI for C). Panels A/B/C show representative pictures using a regular fluorescence microscope, which was used to quantify GFP-positive cell incorporation (G). Substantial numbers of GFP-positive cells incorporated into the cuffed femoral artery segment, particularly in the adventitia (G). Panels D/E/F show a striking example of a section of a cuffed arterial segment that is completely occluded by neointima, which has been visualized using a confocal fluorescence microscope. A detail of the merged picture F is shown in H, illustrating that most of the bone marrow derived GFP-positive cells are located in the adventitia, although various GFP-positive cells can be found dispersed throughout the neointima.