Differential Response of Stro-1+ and Stro-1− Shed to Er,Cr:YSGG Laser Stimulation: Viability, Matrix Production and Lineage Commitment

TL;DR

This study shows that different types of stem cells respond differently to laser treatment, affecting their ability to produce matrix and specialize into bone cells.

Contribution

The study reveals that stem cell maturation status modulates responsiveness to Er,Cr:YSGG laser irradiation in a power-dependent manner.

Findings

Laser exposure increased collagen synthesis in STRO-1+ cells at 0.25 W after 7 days.

Osteogenic differentiation was selectively promoted by laser irradiation, with increased ALP expression and mineral deposition.

Adipogenesis was reduced following 0.10 W laser exposure, while chondrogenic potential remained unaffected.

Abstract

Stem cell heterogeneity represents a critical yet underexplored variable in laser-assisted regenerative strategies. While photobiomodulation has been shown to influence mesenchymal stem cell (MSC) behavior, it remains unclear whether stem cell maturation status modulates responsiveness to Er,Cr:YSGG irradiation. This study investigated the differential response of magnetically separated STRO-1+ and STRO-1− SHED subpopulations to low-power Er,Cr:YSGG laser stimulation (0.10 W and 0.25 W), focusing on viability, extracellular matrix production, and lineage commitment. STRO-1+ cells comprised 13.4% ± 1.2% of the total Stem Cells from Human Exfoliated Deciduous teeth (SHED) population. Laser exposure did not impair metabolic activity in either subpopulation. Collagen synthesis demonstrated a power- and time-dependent increase, with maximal enhancement observed in STRO-1+ cells at 0.25 W after 7 days. Laser irradiation selectively promoted osteogenic differentiation, as evidenced by increased alkaline phosphatase (ALP) expression at 0.10 W and enhanced mineral deposition, while chondrogenic potential remained unaffected and adipogenesis was reduced following 0.10 W exposure. These findings suggest that ALP expression is temporally and power-dependently modulated during osteogenic progression. Overall, Er,Cr:YSGG photobiomodulation does not uniformly affect heterogeneous SHED populations but modulates lineage allocation and extracellular matrix deposition in a maturation- and power-dependent manner. Integrating stem cell subpopulation selection with laser-based bioactivation may represent a strategy to refine regenerative endodontic and biomaterial-guided therapies.

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