Stromal phenotype of dental follicle stem cells

Developmental Anomalies in Human Teeth: Odontoblastic Differentiation in Hamartomatous Calcifying Hyperplastic Dental Follicles Presenting with DSP, Nestin, and HES1

Hyperplastic dental follicles (HDFs) represent odontogenic hamartomatous lesions originating from the pericoronal tissues and are often associated with impacted or embedded teeth. These lesions may occasionally feature unique calcifying bodies, known as calcifying whorled nodules (CWNs), characterized by stromal cells arranged in a whorled or spiral fashion. CWNs are typically observed in multiple calcifying hyperplastic dental follicles or regional odontodysplasia. In our study, we examined 40 cases of HDFs, including nine instances with characteristics of CWNs, referred to as calcifying hyperplastic dental follicles (CHDFs), which are infrequently accompanied by odontodysplasia. The median ages of the HDFs and CHDFs were 16 (ranging from 3 to 66) and 15 (ranging from 11 to 50) years, respectively. The lower third molars were the most frequently affected by HDSFs and CHDFs, followed by the upper canines. A histological examination was conducted on all 40 cases, with an immunohistochemical analysis performed on 21 of them. Among the cases with CWN, nine affected a single embedded tooth, with one exception. CWNs exhibited diverse calcifications featuring sparse or entirely deposited psammoma bodies, and some displayed dentinoid formation. Immunohistochemically, the stromal cells of HDFs were frequently positive for CD56 and nestin. By contrast, CWNs were negative for CD56 but positive for nestin as well as hairy and enhancer split 1 (HES1), with a few dentin sialoprotein (DSP)-positive calcified bodies. Our results revealed that hamartomatous CHDFs can impact multiple and single-embedded teeth. CWNs composed of nestin and HES1-positive ectomesenchymal cells demonstrated the potential to differentiate into odontoblasts and contribute to dentin matrix formation under the influence of HES1. This study is the first report documenting odontoblastic differentiation in HDFs. The rare occurrence of HDFs and CHDFs contributes to limited comprehension. To prevent misdiagnosis, a better understanding of these conditions is necessary.

Advances in combined application of dental stem cells and small-molecule drugs in regenerative medicine

Teeth are a kind of masticatory organs of special histological origin, unique to vertebrates, playing an important role in chewing, esthetics, and auxiliary pronunciation. In the past decades, with the development of tissue engineering and regenerative medicine, the studies of mesenchymal stem cells (MSCs) gradually attracted the interest of researchers. Accordingly, several types of MSCs have been successively isolated in teeth or teeth-related tissues, including dental pulp stem cells, periodontal ligament stem cells, stem cells from human exfoliated deciduous teeth, dental follicle stem cells, stem cells from apical papilla and gingival mesenchymal stem cells. These dental stem cells (DSCs) are easily accessible, possess excellent stem cell characteristics, such as high proliferation rates and profound immunomodulatory properties. Small-molecule drugs are widely used and show great advantages in clinical practice. As research progressed, small-molecule drugs are found to have various complex effects on the characteristics of DSCs, especially the enhancement of biological characteristics of DSCs, which has gradually become a hot issue in the field of DSCs research. This review summarizes the background, current status, existing problems, future research directions, and prospects of the combination of DSCs with three common small-molecule drugs: aspirin, metformin, and berberine.

Maxillofacial-Derived Mesenchymal Stem Cells: Characteristics and Progress in Tissue Regeneration

Maxillofacial-derived mesenchymal stem cells (MFSCs) are a particular collective type of mesenchymal stem cells (MSCs) that originate from the hard and soft tissue of the maxillofacial region. Recently, many types of MFSCs have been isolated and characterized. MFSCs have the common characteristics of being extremely accessible and amazingly multipotent and thus have become a promising stem cell resource in tissue regeneration. However, different MFSCs can give rise to different cell lineages, have different advantages in clinical use, and regulate the immune and inflammation microenvironment through paracrine mechanisms in different ways. Hence, in this review, we will concentrate on the updated new findings of all types of MFSCs in tissue regeneration and also introduce the recently discovered types of MFSCs. Important issues about proliferation and differentiation in vitro and in vivo, up-to-date clinical application, and paracrine effect of MFSCs in tissue regeneration will also be discussed. Our review may provide a better guide for the clinical use of MFSCs and further direction of research in MFSC regeneration medicine.

Characteristics, Classification, and Application of Stem Cells Derived from Human Teeth

Since mesenchymal stem cells derived from human teeth are characterized as having the properties of excellent proliferation, multilineage differentiation, and immune regulation. Dental stem cells exhibit fibroblast-like microscopic appearance and express mesenchymal markers, embryonic markers, and vascular markers but do not express hematopoietic markers. Dental stem cells are a mixed population with different sensitive markers, characteristics, and therapeutic effects. Single or combined surface markers are not only helpful for understanding the subpopulation of mixed stem cell populations according to cell function but also for improving the stable treatment effect of dental stem cells. Focusing on the discovery and characterization of stem cells isolated from human teeth over the past 20 years, this review outlines the effect of marker sorting on cell proliferation and differentiation ability and the assessment of the clinical application potential. Classified dental stem cells from markers and functional molecules can solve the problem of heterogeneity and ensure the efficacy of cell therapy strategies including dentistry, neurologic diseases, bone repair, and tissue engineering.

Dental Follicle Cells: Roles in Development and Beyond

Dental follicle cells (DFCs) are a group of mesenchymal progenitor cells surrounding the tooth germ, responsible for cementum, periodontal ligament, and alveolar bone formation in tooth development. Cascades of signaling pathways and transcriptional factors in DFCs are involved in directing tooth eruption and tooth root morphogenesis. Substantial researches have been made to decipher multiple aspects of DFCs, including multilineage differentiation, senescence, and immunomodulatory ability. DFCs were proved to be multipotent progenitors with decent amplification, immunosuppressed and acquisition ability. They are able to differentiate into osteoblasts/cementoblasts, adipocytes, neuron-like cells, and so forth. The excellent properties of DFCs facilitated clinical application, as exemplified by bone tissue engineering, tooth root regeneration, and periodontium regeneration. Except for the oral and maxillofacial regeneration, DFCs were also expected to be applied in other tissues such as spinal cord defects (SCD), cardiomyocyte destruction. This article reviewed roles of DFCs in tooth development, their properties, and clinical application potentials, thus providing a novel guidance for tissue engineering.

Immunohistochemical expression of CD56 in dog (Canis familiaris) odontogenesis

AIM

To investigate the expression of CD56 in dog odontogenesis in order to elucidate the expression found in ameloblastomas.

MATERIALS AND METHODS

Immunohistochemical analysis of CD56 expression of developing dog teeth in the bud, cap and bell stages including the remnants of the dental lamina.

RESULTS

Weak CD56 expression was observed in the dental epithelium during the bud stage with intense staining of certain peripheral epithelial cells. Positive staining of epithelial cells was also observed in the cap stage with intense staining of the inner enamel epithelium at this stage. During the bell stage the staining was concentrated on the cervical loop areas. The dental papilla revealed positive staining throughout the cap and bell stages while the dental follicle stained intensely positive throughout all the phases examined. The dental lamina and Serres rests also stained positive for CD56.

CONCLUSIONS

The expression of CD56 in dog odontogenic tissue varies according to the stage of tooth development. There is a positive correlation between the positive staining observed in ameloblastomas and their odontogenic cells of origin.

Dental stem cells and their sources

The search for more accessible mesenchymal stem cells than those found in bone marrow has propelled interest in dental tissues. Human dental stem/progenitor cells (collectively termed dental stem cells [DSCs]) that have been isolated and characterized include dental pulp stem cells, stem cells from exfoliated deciduous teeth, stem cells from apical papilla, periodontal ligament stem cells, and dental follicle progenitor cells. Common characteristics of these cell populations are the capacity for self-renewal and the ability to differentiate into multiple lineages. In vitro and animal studies have shown that DSCs can differentiate into osseous, odontogenic, adipose, endothelial, and neural-like tissues.