Fig. 6.

BM-MSCs cultured in PS2 demonstrated the most consistent surface marker expression profiles. A Representative gating strategy for BD Lyoplate™ flow cytometric analysis. Surface markers were then categorised according to their expression level across all samples. B Heatmap showing per cent positive expression of the 78 markers (rows) which displayed variable expression levels among samples (columns). No scaling was applied to rows, both rows and columns were clustered using correlation distance and average linkage. Cluster analysis demonstrates considerable variability due to both donor and culture media, except in the case of PS2 where MSCs from all three donors clustered together, indicating similarity in surface marker expression. C Principal component analysis on the global surface immunophenotype confirms less variability in surface marker expression profile when BM-MSCs are isolated and expanded in PS2 medium. No scaling was applied to rows; SVD with imputation was used to calculate principal components. The X and Y axes show principal component 1 and principal component 2 that explain 39.1% and 19.4% of the total variance, respectively. Prediction ellipses are such that with probability 0.95, a new observation from the same group will fall inside the ellipse. Media conditions and individual donors are displayed (n = 15 data points). PCA segregated MSCs cultured in PS2 and PL into distinct clusters which were separate from MSCs cultured in FBS-containing medium. MSCs cultured in PS2 displayed the lowest variability with all samples clustering tightly together