Abstract:

Stem cells from the apical papilla (SCAP) represent a valuable dental mesenchymal stem cell population with high proliferative and regenerative potential. The present study investigated the effects of long-term in vitro expansion on the proliferative behavior, senescence progression, phenotypic stability, and viability of SCAP. Cells were isolated from the apical papilla of developing human third molars and cultured under standard conditions for up to 40 passages over a period of 177 days. Population doubling (PD) time analysis revealed three distinct growth phases, including an initial adaptation phase, a prolonged period of stable proliferation, and a late phase characterized by significantly increased doubling times indicative of replicative senescence. Flow cytometric analysis demonstrated sustained expression of mesenchymal stem cell markers CD71, CD90, and STRO-1 at both early and late passages, with no statistically significant differences observed. In addition, SCAP preserved high viability following cryopreservation. These findings indicate that SCAP retain their mesenchymal stem cell phenotype and functional stability during extended in vitro cultivation, supporting their suitability for experimental and potential regenerative applications, with mid-passage cells representing the optimal window for use.
Keywords: Stem Cells from Apical Papilla (SCAP), long-term cultivation, stem cells aging, cell senescence, population doubling