Fig. 2

(a) CK activity after 3 and 7 days of myogenic differentiation of 2D co-cultures of Mb and ADSC under serum-free conditions (0 ng/ml GDF11). Multiple comparisons between different groups within the same time period were performed with one-way ANOVA with Tukey‘s multiple comparisons test or Friedman test with Dunn‘s correction as appropriate (n = 3). Levels of significance were * p < 0.05, ** p < 0.01, *** p < 0.001. Paired t-test was used to compare same groups over different time periods (3 days vs. 7 days) (n = 3). Level of significance was ## p < 0.01; (b) Desmin staining of co-cultures of Mb and ADSC after 7 days of differentiation under serum-free (top left), serum-free + 25 ng/ml GDF11 (top right), serum-free + 100 ng/ml GDF11 (bottom left), and serum-free + 500 ng/ml GDF11 (bottom right) differentiation