FIG. 4.

Effects of ES on gene expression. (a) Quantitative real-time PCR (qRT-PCRs) for markers associated to cardiac differentiation, after 1 and 3 days of monophasic (M) and biphasic (B) ES. Data are normalized relative to the unstimulated (U) cells cultured in the same conditions and time points. Values represent the mean±SD gene expression measured from six independent experiments of ES (one-way ANOVA and Bonferroni post-tests vs control U; *P≤0.05, **P≤0.01). (b) Expression of mRNA for Ca²⁺ low-voltage-activated channels in unstimulated (U) and in monophasic (M) and biphasic (B) stimulated cells at day 1 and day 3. Human atrial biopsy (hH) was used as control. Image shows a typical experiment out of the three performed relative to a donor patient. In general, early genes are upregulated more efficiently with biphasic stimulation, while structural/functional genes are upregulated more efficiently after 3 days, both upon monophasic and biphasic electric stimulation.