Fig. 2.

Removal of the blood vessel markedly increased the transduction of MSC-EM-initiating cells in the UCPs. To compare the transduction efficiency of differently prepared UCPs, each donor UC was prepared in all methods, and different donors were used for different concentrations of viral vectors coding for fluorescent reporter proteins. The outgrown MSC-EMs were analyzed by flow cytometry. In the upper graph, the x-axis shows the different vector concentration, the y-axis the percentage of fluorescent-protein-positive cells in induced MSC-EMs. In the lower graph, the variation of gene marking among MSC-EMs from the same UCPs is shown. Depicted are the means and the standard deviations. n > 7. Statistical tests were performed with Kruskal-Wallis and Dunn’s multiple comparison tests. Only significant differences are indicated. * = p < 0.05, *** = p < 0.001, T.U. = transduction units, MSC-EM = mesenchymal stromal cell explant monolayer, Std = standard preparation, BLOP = blood vessel cut open, BLRV = blood vessel completely removed