Dottorato in MEDICINA SPERIMENTALE

Titolo della tesi: “Valutazione del potenziale angiogenico di cellule mesenchimali staminali adulte derivate dalla polpa dentaria umana”

Dental pulp has been revealed as an accessible and a rich source of mesenchymal stem cells (MSCs) and its biological potential is currently under intense investigation. MSCs from dental pulp stem cells (DPSC) have been indicated as a heterogeneous population oriented not only in repairing dentine but also in maintaining vascular and nervous homeostasis of the teeth. We sought to verify the phenotype of cells isolated from dental pulp of young donors and to investigate in vitro their role as pericyte-like cells. Specifically, we evaluated how different culture conditions can modulate expression of pericyte markers in DPSC and their capacity to stabilize endothelial tubes in vitro. DPSC cultured in standard conditions expressed MSC markers and demonstrated to contain a population expressing the pericyte marker NG2. These DPSC were associated with low sprouting capacity in extracellular (EC) Matrix and limited ability in retaining tubes formed by endothelial cells in a coculture angiogenesis model. When cultured in endothelial growth medium (EGM-2), DPSC significantly upregulated NG2. The resulting population conserved the stem marker CD73 but was negative for calponin and endothelial markers. EGM-2-conditioned DPSC showed a higher sprouting ability in EC Matrix and efficient association with human umbilical vein endothelial cells allowing the partial retention of endothelial tubes for several days. Among growth factors contained in EGM-2 we identified basic fibroblast growth factor (FGF) as mainly responsible for NG2 upregulation and long-term stabilization of endothelial tubes. According to the in vitro analysis, DPSC represent an effective source of pericytes, and the appropriate culture conditions could result in a population with a promising ability to stabilize vessels and promote vascular maturation.