Figure 5

Inflammation and vascularization of scaffolds after three weeks implantation. (A) Early expression of human specific macrophage colony stimulating factor-1 (CSF-1) one week after implantation was higher in mono-culture, although not statistically significant (P = 0.079). Three weeks after implantation a difference could no longer be found. (B) Staining for CD11b, a protein subunit of the macrophage-1 antigen, was positive on the surface of the implanted constructs three weeks after implantation for both experimental groups. (C) Functional blood vessels were identified on H & E staining by the presence of erythrocytes in the lumen and through CD31-staining. Nuclei were stained with DAPI (blue). 20x magnification, scale bar = 100 μm. (D) The expression of ankyrin repeat domain 1 (ANKRD1) associated with EC activation was up-regulated in mono-cultured ECs compared with empty controls. * = P <0.05. (E) The distribution of vessels three weeks after implantation showed a higher percentage of vessels >50 μm in the EC-group: however, it was not statistically significant. (F) The percentage of vessels <20 μm was highest in EC/MSC-constructs. * = P <0.05. (G) Both cellular constructs had a higher vascular density at the end of the experimental period compared with empty control scaffolds. ** = P <0.01. The difference between the experimental groups was not statistically significant. The same tendency was observed for the total area fraction of CD31+ cells, but statistically significant differences were not found. DAPI, 4',6-diamidino-2-phenylindole; ECs, endothelial cells; MSC, meschymal stem cells.