Fig. 3.

Sprouting and intussusceptive angiogenesis on pleural plexus. The pleural surface of the cardiac lobe is underlaid by a highly ramified capillary plexus originating from and draining to pulmonary vessel branches. a Coverage of approximately 15–25 % of the pleural surface. Bar = 50 μm. b 7 days after pneumonectomy this plexus increases in density, focally resulting in coverage of up to 85 %. Bar = 50 μm. c Numerous small caliber holes with diameters of between 1 and 5 μm as hallmarks of pillar formation (white arrows) show the high intussusceptive angiogenesis activity. Bar = 25 μm. d In less densely packed areas sprouts (red arrowheads) as well as pillars are evident. Bar = 20 μm