Abstract 20069: Serum-Free Culture Conditions Support Human Cardiac Stem Cell Outgrowth

Abstract

Introduction: Autologous cardiac stem cell (CSC) therapies represent an emerging treatment option for patients with congestive heart failure. Unfortunately, straightforward translation to the clinic is limited by traditional culture conditions that are supplemented by ill-defined or xenobiotic components such as fetal bovine serum. As such, overcoming these barriers is the next critical step in developing next generation CSC therapies for clinical use. Methods/Results: Transition of CSC culture methods to serum-free, xeno-free culture conditions demonstrated negligible effects on the overall numbers of cells cultured with equivalent cardiac (c-Kit+; 7.8±0.2 %, p=0.34) and mesenchymal (CD90+; 32±7 %, p=0.57) progenitor content as compared to standard culture conditions. Flow cytometry morphometry demonstrated that serum free cells provide a smaller, more homogeneous cell product. Exposure to hypoxic stress conditions demonstrated equivalent secretion of SDF-1α, SCF, HGF, and VEGF-A with reduced production of the pro-inflammatory cytokine IL-6 from serum-free cells (7±2 fold less; p=0.005). Despite differences in cytokine production, conditioned media from serum-free CSCs promoted similar new vessel formation (37±5 vs. 41±7 % of positive control within a HUVEC tube formation assay; p=0.69) and circulating stem cell recruitment (39±9 vs. 47±12% of the positive control within a transwell assay, p=0.64) when compared to media conditioned by standard cultures. Storage of cell suspensions at 4°C had negligible effects on 12 hour viability (95.3±1.6%, p=0.50), suggesting a shelf life sufficient for transport between institutions. Finally, injection of CSCs through a clinically approved coronary artery perfusion catheter did not alter cell viability (99.2±1.7 % after delivery, p=0.77) while ensuring successful product delivery to the peri-infarct zone. Conclusions: Transitioning CSCs to clinically acceptable protocols provides a more uniform cell product ready for clinical delivery. These findings represent the first published evidence that altered serum-free xeno-free culture conditions can provide a superior CSC cell product with the potential for ready translation to clinical use.