Dental Stem Cells vs. Other Mesenchymal Stem Cells: Their Pluripotency and Role in Regenerative Medicine

Mesenchymal stem cells: A comprehensive methods for odontoblastic induction

BACKGROUND

In the area of oral and maxillofacial surgery, regenerative endodontics aims to present alternative options to conventional treatment strategies. With continuous advances in regenerative medicine, the source of cells used for pulp tissue regeneration is not only limited to mesenchymal stem cells as the non-mesenchymal stem cells have shown capabilities too. In this review, we are systematically assessing the recent findings on odontoblastic differentiation induction with scaffold and non-scaffold approaches.

METHODS

A comprehensive search was conducted in Pubmed, and Scopus, and relevant studies published between 2015 and 2020 were selected following the PRISMA guideline. The main inclusion criteria were that articles must be revolving on method for osteoblast differentiation in vitro study. Therefore, in vivo and human or animal clinical studies were excluded. The search outcomes identified all articles containing the word "odontoblast", "differentiation", and "mesenchymal stem cell".

RESULTS

The literature search identified 99 related studies, but only 11 articles met the inclusion criteria. These include 5 odontoblastic differentiation induction with scaffold, 6 inductions without scaffolds. The data collected were characterised into two main categories: type of cells undergo odontoblastic differentiation, and odontoblastic differentiation techniques using scaffolds or non-scaffold.

CONCLUSION

Based on the data analysis, the scaffold-based odontoblastic induction method seems to be a better option compared to the non-scaffold method. In addition of that, the combination of growth factors in scaffold-based methods could possibly enhance the differentiation. Thus, further detailed studies are still required to understand the mechanism and the way to enhance odontoblastic differentiation.

Cerebrospinal Fluid and Photobiomodulation Effects on Neural Gene Expression in Dental Pulp Stem Cells

Introduction: Dental pulp cells, a unique source of ectomesenchymal pluripotent stem cells, are originated from the skull neural crest. They are considered as one ideal source of cells for the regenerative medicine applications. Cerebrospinal fluid (CSF), a transparent fluid found in the brain and spinal cord, is enriched with electrolytes, proteins, and growth factors such as EGF, bFGF, BDNF, GDNF, and neuropeptides and can be utilized as a trigger in order to induce the neural differentiation. On the other hand, photobiomodulation (PBM), with the ability to prevent cell apoptosis, can induce cell proliferation by means of increasing the ATP synthesis in mitochondria and facilitating the secretion of the growth factors. In this research, we first aimed to isolate and culture the dental pulp stem cells (DPSCs) and subsequently to investigate their potential for neural differentiation. Methods: Human dental pulp stem cells (hDPSCs) were isolated from the pulp tissues using an outgrowth method and subsequently cultured. In order to access the cells' differentiation potential, cells were firstly classified into four groups which were treated with CSF, gallium aluminum arsenide diode laser irradiation (808 nm; 30 mW power output) and a combination of both, while the fourth group was considered as the control. MTT assay was then used to examine the viability of cells following the treatments. After 4, 7, and 14 days the cell morphology in the treated groups was evaluated while RT-PCR was used in order to evaluate the Nestin and β-tubulinIII neural gene marker expressions. Results: It was shown that PBM has the ability to elevate the proliferation of DPSCs. Also, the differentiated morphology was obvious in the CSF treated group, especially on day 14 with the formation of three-dimensional (3D) structures. The results of gene expression analysis showed that on the fourth day of post-treatment, Nestin and β-tubulinIII gene expressions were reduced in all groups while a rising trend in their expression was observed subsequently on days 7 and 14. Conclusion: In accordance with previous studies, including functional and protein base researches, it has been demonstrated that CSF has a direct role in neural induction. Although past works have been significant, none of them shows a 3D structure. In this article, we investigated the dual effect of PBM and CSF. Initial results confirmed the upregulation of neural-related transcription factors. The 3D organization of the formed tissue could imply the initiation of organogenesis which has not been reported before. In sum, the dual effect of CSF and PBM has been shown to have the potential for contributing to the initiation of neurogenesis and organogenesis.

Dental Pulp Stem Cells: Isolation, Characterization, Expansion, and Odontoblast Differentiation for Tissue Engineering

Tissue engineering is an interdisciplinary area offering a promising approach by the use of stem cells combined with scaffolds and signaling factors for regeneration of damaged or lost tissues. Incorporation of a sufficient number of cells which do not elicit the immunoreaction in the body is a pivotal element for successful tissue formation using this method. Stem cells exhibiting strong capacity to self-renew and differentiate into different cell types are considered as a potent cell source. Among various cell sources, dental pulp stem cells (DPSCs) are widely under investigation due to the fact that they are simply obtainable from extracted third molars or orthodontically extracted teeth and show an excellent potential for clinical application and also their harvesting method is minimally invasive. DPSCs are odontogenic progenitor cells with clonogenic abilities, rapid proliferation rates, and multiple differentiation potentials. Here, we describe protocols that allow 1) the isolation of DPSCs from a single tooth; 2) the characterization of human mesenchymal stem cells markers of DPSCs by flow cytometry; 3) the culture growth of DPSCs in 2D (in cell culture flasks) and 3D (by 3D printing of cell-laden constructs); and 4) the in vivo evaluation of differentiation potential of DPSCs.