Figure 2.

Identification of ALDH^br cells in the atrial and ventricular population from 8 week-old mice. Flow cytometric analysis of ALDH activity (a). Left panels: atrial and ventricular cells were selected according to forward scatter (FSC) and side scatter (SSC) properties using the gated region. Middle panels: cells incubated with Aldefluor substrate and the specific inhibitor of ALDH, DEAB, were used to establish baseline fluorescence of these cells and to define the ALDH^br region (R2) as less than 0.1% of total events. Right panels: cell incubation with Aldefluor in the absence of inhibitor induced a shift in FL1 fluorescence defining the ALDH^dim⁡ (R1) and the ALDH^br (R2) population. In the example shown, not all of the atrial cells exhibiting a shift in FL1 fluorescence in the absence of inhibitor were found in the gated region R2, suggesting that atrial ALDH^br cells may have been underestimated (b). Bar histogram showing percent ALDH^br cells (mean, SD) in the ventricular and atrial population.