Osteogenic Differentiation Induced by Dental Pulp Stem Cells Secretome: A Dose‐Dependent Comparative Study
Mahdi Kadkhodazadeh, Reza Amid, Aida Kheiri, Sayna Shamszadeh, Forough ShamsABSTRACT
Objectives
To investigate the effects of dental pulp stem cell‐derived conditioned medium (DPSC‐CM) on the proliferation, migration, and osteogenic differentiation of periodontal ligament stem cells (PDLSCs). Primary goals were to (i) identify the optimal DPSC‐CM' concentration and (ii) evaluate its effect both independently (under Growth Medium, [GM]) and synergistically (under Osteogenic Medium [OM]).
Materials and Methods
DPSC‐CM was collected, and an initial screen was conducted to determine their maximum non‐toxic concentration (MNTS). For functional assays, three non‐cytotoxic concentrations (V/V) (10% [CM‐10], 30% [CM‐30], 50% [CM‐50]) were selected. While cytokine release profile, cell proliferation, and migration were assessed under GM conditions, differentiation was evaluated over 14d under both GM and OM conditions ( p < 0.05).
Results
The MNTS was established as CM‐50. DPSC‐CM promoted all cellular activities in a non‐linear, concentration‐specific manner. CM‐10 demonstrated the most beneficial effects; it yielded the highest levels of TGF‐β1 and VEGF secretion ( p < 0.05), and significantly increased proliferation, alkaline phosphatase activity, and expression of osteogenic/angiogenic markers than CM‐50 and CM‐30 over time. However, peak cell migration was observed on Day 2 for both CM‐30 and CM‐10. While DPSC‐CM alone enhanced osteogenesis, the highest induction was achieved under OM conditions.
Conclusions
DPSC‐CM is a potent osteoinductive agent, enhancing proliferation, migration, and differentiation in a non‐linear concentration‐specific manner. The lowest concentration proved optimal for their proliferative and osteogenic properties, suggesting a Hormesis‐like effect where higher doses may become sub‐optimal due to inhibitory factors.