Human cardiosphere-derived cells from patients with chronic ischaemic heart disease can be routinely expanded from atrial but not epicardial ventricular biopsies

Abstract

To investigate the effects of age and disease on endogenous cardiac progenitor cells, we obtained right atrial and left ventricular epicardial biopsies from patients (n = 22) with chronic ischaemic heart disease and measured doubling time and surface marker expression in explant- and cardiosphere-derived cells (EDCs, CDCs). EDCs could be expanded from all atrial biopsy samples, but sufficient cells for cardiosphere culture were obtained from only 8 of 22 ventricular biopsies. EDCs from both atrium and ventricle contained a higher proportion of c-kit+ cells than CDCs, which contained few such cells. There was wide variation in expression of CD90 (atrial CDCs 5-92 % CD90+; ventricular CDCs 11-89 % CD90+), with atrial CDCs cultured from diabetic patients (n = 4) containing 1.6-fold more CD90+ cells than those from non-diabetic patients (n = 18). No effect of age or other co-morbidities was detected. Thus, CDCs from atrial biopsies may vary in their therapeutic potential.

Fig. 1

Expansion of EDCs and CDCs from atrial and ventricular biopsies. a Considerable variation was observed in the time taken for culture of confluent explant- and cardiosphere-derived cells and in the number of cells obtained. b The number of EDCs generated from atrial biopsies correlated with the number from ventricular biopsies. c The time taken for atrial EDCs to reach confluence correlated inversely with the doubling time of CDCs

Fig. 2

Cell surface markers on EDCs and CDCs. a Representative flow cytometry plots for CD117 (c-kit), CD90 and CD105 (with isotype controls in grey) in CDCs from atrial (top) and ventricular (bottom) biopsy samples. b Expression of cell surface markers by EDCs and CDCs from atrial and ventricular biopsies (n = 3 for atrial and ventricular EDCs, n = 22 for atrial CDCs and 8 for ventricular CDCs; *p < 0.05 compared with atrial EDCs, †p < 0.05 compared with ventricular EDCs). c The time taken for culture of confluent EDCs inversely correlated with CD90 expression in CDCs and d the doubling time of CDCs inversely correlated with CD105 expression in CDCs. e Atrial CDCs from diabetic patients (n = 4) contained significantly more CD90+ cells than those from non-diabetic patients (n = 18; *p < 0.05 compared with non-diabetic patients). Error bars show standard errors

Fig. 3

Immuno-staining of CDCs. Representative confocal images from immuno-staining of atrial CDCs for actin filaments, CD90, discoidin domain receptor 2 (DDR2), smooth muscle actin (SMA) and troponin-T (TnnT). Cells from diabetic patients (right 2 panels) contained higher levels of the fibroblast marker DDR2 than those from non-diabetic patients (left 2 panels) and showed low expression of TnnT after treatment with differentiation medium containing dimethyl sulphoxide (DMSO) for 2 weeks. Scale bars = 50 μm