The clinical application of cardiosphere-derived cells (
CDCs) to treat
cardiac disease has gained increasing interest over the past decade. Recent clinical trials confirm their regenerative capabilities, although much remains to be elucidated about their basic biology. To develop this new treatment modality, in a cost effective and standardized workflow, necessitates the creation of cryopreserved cell lines to facilitate access for cardiac patients requiring urgent
therapy. Cryopreservation may however lead to alterations in cell behavior and potency. The aim of this study was to investigate the effect of cryopreservation on canine
CDCs.
CDCs and mesenchymal stem cells (MSCs) isolated from five dogs were characterized.
CDCs demonstrated a population doubling time that was unchanged by cryopreservation (fresh vs. cryopreserved; 57.13 ± 5.27 h vs. 48.94 ± 9.55 h, P = 0.71). This was slower than for MSCs (30.46 h, P < 0.05). The ability to form clones, self-renew, and commit to multiple lineages was unaffected by cryopreservation. Cryopreserved
CDCs formed larger cardiospheres compared to fresh cells (P < 0.0001). Fresh
CDCs showed a high proportion of CD105+ (89.0% ± 4.98) and CD44+ (99.68% ± 0.13) cells with varying proportions of CD90+ (23.36% ± 9.78), CD34+ (7.18% ± 4.03) and c-Kit+ (13.17% ± 8.67) cells. CD45+ (0.015% ± 0.005) and CD29+ (2.92% ± 2.46) populations were negligible. Increasing passage number of fresh
CDCs correlated with an increase in the proportion of CD34+ and a decrease in CD90+ cells (P = 0.003 and 0.03, respectively). Cryopreserved
CDCs displayed increased CD34+ (P < 0.001) and decreased CD90+ cells (P = 0.042) when compared to fresh cells. Overall, our study shows that cryopreservation of canine
CDCs is feasible without altering their stem characteristics, thereby facilitating their utilization for clinical trials. © 2017 International Society for Advancement of Cytometry.