Identification and characterization of stem cells in three different oral structures by immunohistochemistry. An in vitro study.

Abstract

Background: Stem cells are undifferentiated cells with the capacity for self-renewal and differentiation, playing a key role in tissue repair and regeneration.

Aim: The study aims to assess and compare the expression pattern of stem cell markers like CD44, CD34, and OCT4 in the gingival mucosa, palatal mucosa, and dental pulp from both permanent teeth and shedding primary teeth.

Materials and methods: Sixty tissue samples were taken from the patients without any medical history undergoing standard dental operations. We performed immunohistochemical staining of CD44, CD34, and OCT4 antibodies in formalin-fixed paraffin-embedded tissue sections. The staining intensity and distribution were measured using a semiquantitative immunoreactive score. One-way analysis of variance (ANOVA) analysis was conducted to compare the levels of marker expression between various tissues.

Statistical analysis: Data were analysed using Microsoft Excel and IBM Statistical Package for the Social Sciences Statistics, with Chi-square and one-way ANOVA tests applied and P < 0.05 considered significant.

Results: CD44 demonstrated strong positivity predominantly in the basal and suprabasal epithelial layers, with higher staining intensity observed in the palatal mucosa compared to other tissues. CD34 expression in dental pulp samples exhibited distinctive vascular-associated staining patterns, while gingival and palatal lamina propria showed prominent endothelial cell positivity. OCT4 expression was negative across all four tissue groups.

Conclusion: CD44 showed significant epithelial expression, its widespread distribution limits, and its specificity as a stem cell marker. CD34 proved reliable for identifying vascular components but may not represent all hematopoietic stem cells. The absence of OCT4 expression suggests tissue stability without evidence of pluripotent stem cell activity.