Integration properties of Wharton's jelly-derived novel mesenchymal stem cells into ventricular slices of murine hearts.

Wharton's jelly (WJ) is a rich source of multiple-lineage differentiating cells, recently proposed for cell replacement therapy. However, their ability to integrate into the cardiac tissue has not been elucidated, yet. We employed in vitro cardiac transplantation models to investigate the capacity of a novel population of human WJ-derived mesenchymal stem cells (nMSCs) to integrate into both living and ischemic cardiac tissue. NMSCs were characterized for the expression of stem/progenitor cell genes and proteins, as well as for multi-lineage differentiation potential. To assess their integration properties, nMSCs were cocultured with either living or ischemic embryonic murine ventricular slices. Immunohistochemical analyses were performed on cryosections of cocultured preparations to allow human cells tracking within the cocultures. Results showed that nMSCs shared MSC and endothelial colony-forming cell characteristics at gene, protein, and functional levels. NMSCs were markedly chemoattracted towards the ventricular slices, integrating robustly into the depth of both living and ischemic cardiac tissue. In conclusion, the functional ability of WJ-derived cells to populate the cardiac tissue could be validated in vitro. The transplantation models described could be further used to depict the mechanisms of WJ-derived cells integration into the cardiac tissue, contributing to optimization of reliable cell therapies for cardiac repair.