Applications of stem cells in interdisciplinary dentistry and beyond: an overview

Curcumin attenuates replicative senescence in human dental follicle cells and restores their osteogenic differentiation

OBJECTIVE

This study aimed to examine the therapeutic effects of curcumin against replicative senescence in dental follicle cells (DFCs).

METHODS

Human DFCs were cultured in Dulbecco's Modified Eagle Medium with growth supplements. Replicative senescence in DFCs at different passages was assessed using β-galactosidase activity assay. Cell proliferation and size of DFCs at different passages were determined by CCK-8 kit and microscopy method, respectively. In addition, curcumin's effect on replicative senescence, cell proliferation, and size of DFCs at different passages was analyzed. Using western-blot analysis and siRNA-mediated gene silencing, we determined the molecular mechanisms involved in curcumin's effect against replicative senescence and osteogenic differentiation in DFCs at different passages.

RESULTS

We observed decreased proliferation and increased cell size and replicative senescence in cultured human DFCs at higher passages. Intriguingly, despite not showing any effect on cell size, curcumin (50 μM) significantly restored proliferation ability in DFCs and inhibited their replicative senescence. Concerning mechanisms, we found that curcumin inhibits replicative senescence in DFCs via down-regulation of senescence markers (P16 & P21) and restoration of proliferation markers (E2F1 & P53). Additionally, curcumin also rescued the osteogenic differentiation potential in higher-passage DFCs via restoration of osteogenic markers RUNX2 and OPN.

CONCLUSION

Our findings reveal for the first time that curcumin could act as a potential anti-senescence therapeutic for DFCs via regulation of proliferation, senescence, and osteogenic differentiation markers.

Stem-Cell Therapy: Filling Gaps in Oro-Maxillofacial Region

How do stem cells function? Why should we, as dentists, care about stem cells? How might dental procedures be substituted by stem cells? Are stem cells capable of regenerating a tooth or temporomandibular joint (TMJ)? Although the ability to regenerate a destroyed tissue has been known for a while, research into regenerative medicine and dentistry has made significant strides in molecular biology. A paradigm shift in the therapeutic toolbox for dental and oral diseases is likely to result from a growing understanding of biological concepts in the regeneration of oral/dental tissues along with stem cell research, leading to an intense search for "biological solutions to biological problems." Among other tissues, orofacial tissues effectively separate stem cells from human tissues. Because they can self-renew and produce different cell types, stem cells offer novel techniques for regenerating damaged tissues and curing illnesses. A number of significant milestone successes have shown their practical applicability, traditional biomaterial-based treatments in regenerative dentistry as therapeutic alternatives that offer regeneration of damaged oral tissues rather than merely "filling the gaps." In order to use these innovative accomplishments for patient well-being, the ultimate goal of this ground-breaking technology, well-designed clinical studies must be implemented as a crucial next step. The review's objective is to briefly synthesize the literature on stem cells in terms of their traits, subtypes, and uses for dental stem cells. It has been highlighted that stem cell therapy has the ability to treat craniofacial abnormalities and regenerate teeth in the oral and maxillofacial regions.

Knowledge and Attitude of Undergraduate Students and Interns toward Stem Cells and Their Implications in Dentistry: A Cross-sectional Study

AIM

The primary ideology of this research was to evaluate both the knowledge and attitude of undergraduate students and interns regarding stem cells and their use in dentistry.

MATERIALS AND METHODS

A cross-sectional observatory study was conducted among 310 dental students of Jazan University by making use of a self-explanatory questionnaire, containing a set of 25 questions and was sent as e-mail through Google e-forms.

RESULTS

There was a good response rate of around 81.2%, of which 80.16% were aware of the fact that stem cells are unspecialized types of cells that come with the potential to turn into any cell type. Almost 65.08% of the participants considered the possibility to continue root formation post-trauma as the fundamental use of stem cells, and a majority (71.43%) of the participants showed great interest in garnering more knowledge and training in the area of stem cells. About 50% of the participants showed strong opposition to the concept of embryonic stem cells as these are basically fetched from an aborted fetus or from an embryo. There was a major section of the participants (79.76%) who were even keen on organizing more programs to create public awareness regarding stem cells. Mean knowledge and attitude scores among the participants were reported to be 7.57 ± 3.10 and 36.04 ± 6.51 respectively.

CONCLUSION

Overall, the level of knowledge and attitude of dental students and interns at Jazan University towards stem cells and their implications in dentistry can be interpreted as adequate.

CLINICAL SIGNIFICANCE

Advanced training and awareness campaigns on stem cells and dentistry would improve their knowledge and attitude.

Analysis of Pulp Tissue Viability and Cytotoxicity of Pulp Capping Agents

The present research study assessed the cell viability and cytotoxic effect of mineral tri-oxide aggregate (MTA), Tetric N-Bond Universal bonding agent, Theracal PT (pulpotomy treatment), and platelet-rich fibrin (PRF) as pulp capping agents on human dental pulp stem cells (hDPSCs). The cells were isolated from the pulp tissue of an extracted healthy permanent third molar. After four passages in Dulbecco’s Modified Eagle’s Medium, the primary cells were employed for the investigation. The test materials and untreated cells (negative control) were subjected to an Methylthiazol-diphenyl-tetrazolium (MTT) cytotoxicity assay and assessed at 24-, 48-, and 72-h intervals. The Wilcoxon matched-paired t-test and Kruskal−Wallis analysis of variance (ANOVA) test were applied (p < 0.05). PRF imparted the highest cell viability at 48 h (p < 0.001), followed by MTA, Theracal PT, and Tetric N-Bond. Similarly, PRF had the highest potential to enhance cell proliferation and differentiation (p < 0.001), followed by Theracal PT, MTA, and the bonding agent at the end of 24 h and 72 h, respectively. Finally, PRF sustained the viability of human primary dental pulp stem cells more effectively than Theracal PT and MTA; however, the application of a Tetric N-Bond as a pulp capping agent was ineffective.

The effects of combination therapy by solid lipid nanoparticle and dental stem cells on different degenerative diseases

Stem cells have multiple therapeutic applications, as well as solid lipid nanoparticles. Solid lipid nanoparticle has appeared as a field of nano lipid technology with various potential applications in drug delivery, clinical medicine and research. Besides, the stem cells have a high proliferation rate and could differentiate into a variety of tissues. Stem cells derived from human dental pulp tissue differ from other sources of mesenchymal stem cells due to their embryonic neural crest source and neurotrophic potential. These consist of both dental pulp stem cells from dental pulp tissues of human permanent teeth and stem cells from human exfoliated deciduous teeth. With the emergence of stem cell banks, stem cells are considering for tissue engineering with respect to therapies attitude and regenerative medicine. The present study aimed to evaluate the advantages and disadvantages of the solid lipid nanoparticle and stem cells combination therapy in different therapeutic applications. The solid lipid nanoparticles have anticancer activity against tumors, induce neural differentiation in pluripotent stem cells, and regulate the mesenchymal stem cells. They also have immunomodulatory effects on human mesenchymal stem cells, the gene transfection efficiency, osteogenic differentiation and bone regeneration. But, the crucial health hazards related to stem cell transplantation such as immune rejection reactions and the interaction with other tissues and the effect of solid lipid nanoparticles must not be neglected. Overall, more experiments need to approve the synergism and antagonism effects of the stem cells and solid lipid nanoparticle combination therapy on different degenerative diseases.

The therapeutic effects of stem cells from human exfoliated deciduous teeth on clinical diseases: a narrative review study

INTRODUCTION

Stem cells isolated from human dental pulp tissue are different from other sources of Mesenchymal stem cells because of their embryonic neural crest sources and neuro-trophic potential. These stem cells consist of dental pulp stem cells from human permanent teeth and stem cells from human exfoliated deciduous teeth.

AIM

In this study, we survey the advantages and disadvantages of these stem cells with therapies attitude.

MAIN TEXT

Stem cells from human exfoliated deciduous teeth with a high proliferation rate could distinguish into a wide types of cells. After stem cell banking appearance, stem cells from human exfoliated deciduous teeth can preserve and use for treatment, especially in regenerative medicine. But the crucial health hazards related to stem cell transplantation, such as immune rejection reactions and the interaction with other tissues, should not be neglected.

CONCLUSION

Further experiments are required to approve the impact of these stem cells on different human disorders.

"Dental Stem Cells": Awareness, knowledge, and attitude of dental professionals-A cross-sectional study

AIM

The present study was conducted with an aim to assess the awareness about existence of dental stem cells among dental professionals.

MATERIALS AND METHODS

A total sample size of 100 dental professionals in the age group of 22-32 years, comprising of 28 interns, 46 postgraduate students, and 26 senior residents from various specialties was selected. A self-administered, hand-delivered, 10-point questionnaire was used to assess the awareness, knowledge, and attitude of dental professionals towards dental stem cells. Results were documented and statistically analyzed using chi-square test.

RESULTS

A total of 72% dental professionals were aware about dental stem cells with dental curriculum books being the main source of information. Note that 81% of positive respondents were aware about the different types and a total of 28% were aware about the procedure to procure dental stem cells. Only 33.3% of positive respondents were aware about existence of dental stem cell banks in India.

CONCLUSION

A high level of awareness about dental stem cells and its applications was noted during the course of this study. A significant association of age and type of practice with awareness of dental stem cells and knowledge regarding their use in developing nondental tissues was observed. A positive attitude towards recommending dental stem cell banking was seen.

Effect of Different Dentin Conditioning Agents on Growth Factor Release, Mesenchymal Stem Cell Attachment and Morphology

INTRODUCTION

EDTA has been considered the gold standard in regenerative endodontic treatments. The aim of this study was to evaluate the effects of different dentin conditioning agents other than EDTA on released growth factors, mesenchymal stem cell attachment, and morphology.

METHODS

Transforming growth factor beta 1, vascular endothelial growth factor, bone morphogenetic protein 2, and fibroblast growth factor 2 release from prepared dentin discs conditioned with 17% EDTA, 10% citric acid, 1% phytic acid (IP6), or 37% phosphoric acid were quantified using the enzyme-linked immunosorbent assay after final irrigation and after 3 days of adipose-derived mesenchymal stem cell (adMSC) seeding. Forty root fragments were prepared from extracted single-rooted teeth. The morphology and attachment of adMSCs on the conditioned root fragments were observed using a scanning electron microscope. Data for growth factor quantification were analyzed using 1-way analysis.

RESULTS

The highest transforming growth factor beta 1 release was observed after citric acid treatment followed by phosphoric acid; there was no significant difference between them, but compared with EDTA and 1% IP6, there were significant differences observed. The enzyme-linked immunosorbent assay detected a very minor exposure of vascular endothelial growth factor and fibroblast growth factor 2 after dentin conditioning, but there were no significant differences between the groups. The greatest bone morphogenetic protein 2 release was observed in the 1% IP6 group, but there were no significant differences between the groups. Three days of adMSC seeding after dentin conditioning has made a dramatic increase in all of the growth factors, and phosphoric acid appeared to be the most effective agent with significant differences compared with the remaining groups. Scanning electron microscopic observations showed that none of the conditioning solutions had an adverse effect on stem cell proliferation and attachment to root dentin. Different cell morphologies like round, oblong, flat, and well-attached cells with developed filopodia were observed in the dentin-conditioned groups.

CONCLUSIONS

Phosphoric acid conditioning could be useful and may have beneficial effects in regenerative endodontic treatments.

Fibroblast growth factor-6 enhances CDK2 and MATK expression in microvesicles derived from human stem cells extracted from exfoliated deciduous teeth

Background: Stem cells from human exfoliated deciduous teeth (SHEDs) are considered one of the most convenient sources of adult stem cells. This study aimed to examine the effect of fibroblast growth factor 6 (FGF-6) on SHEDs and evaluate CDK2 and MATK gene expression in SHED-derived microvesicles (MVs). SHEDs were cultured from deciduous teeth pulp.

Methods: SHEDs were divided into two groups: the control group and test groups, with and without FGF-6 supplementation, respectively. After the third passage, SHED proliferation was assessed by MTT assay. MVs were purified and CDK2 and MATK gene expression was assessed by real-time polymerase chain reaction. SHEDs were identified by their positivity for CD90 and CD73, and negativity for CD45 and CD34.

Results: SHEDs proliferation in the test group was significantly higher than in the control group (P<0.001). mRNA from SHED-derived MVs from the test group exhibited a markedly elevated expression of CDK2 and MATK, (P<0.002 and P<0.005, respectively) in comparison with those of the control group. FGF-6 enhanced the proliferation of SHEDs. Proliferation enhancement is favorable for the production of a large number of stem cells, which will then be beneficial for cell-based therapies.

Conclusions:CDK2 and MATK genes in SHED-derived MVs can be used as molecular biomarkers for SHED proliferation.

Comparative evaluation of the isolation and quantification of stem cells derived from dental pulp and periodontal ligament of a permanent tooth and to assess their viability and proliferation on a platelet-rich fibrin scaffold

BACKGROUND

The present study aims to comparatively evaluate the isolation and quantification of stem cells derived from dental pulp and periodontal ligament of a permanent tooth and to assess their viability and proliferation on a platelet-rich fibrin (PRF) scaffold.

MATERIALS AND METHODS

A total of 15 systemically healthy individuals between the age group of 15-25 years requiring third molar or orthodontic premolar extractions. Teeth were extracted atraumatically and transported to the laboratory. Stem cells were isolated from dental pulp and periodontal ligament. After attaining more than 90% confluency by the 7th day, these cells were tested for their viability and characterization. Stem cells were also incubated with PRF and viability was assessed on the 7th day.

RESULTS

The mean number of cell for dental pulp stem cells (DPSCs) and periodontal ligament stem cell (PDLSC) was statistically insignificant (P > 0.05). The mean live cell viability was compared between DPSC (98.07%) and PDLSC (98%). Both DPSC and PDLSC showed a high percentage of expression of CD73 markers, 30.40% and 29.80%, respectively. However, DPSCs and PDLSCs lacked expression of CD34 expressing only 3.47% and 3.53%, respectively. PRF membrane as a scaffold exhibited no cytotoxic effects on DPCS's or PDLSC's. The cell viability of cells cultured with PRF was statistically insignificant (P > 0.05) when compared to the cells cultured with culture media.

CONCLUSION

The study thus indicates that dental pulp and periodontal ligament are both rich sources of mesenchymal stem cells and can be successfully used for obtaining stem cells. PRF exhibits no cytotoxic effects on the cells and can be used in conjunction with dental stem cells.

Odontogenic epithelial stem cells: hidden sources

The ultimate goal of dental stem cell research is to construct a bioengineered tooth. Tooth formation occurs based on the well-organized reciprocal interaction of epithelial and mesenchymal cells. The dental mesenchymal stem cells are the best explored, but because the human odontogenic epithelium is lost after the completion of enamel formation, studies on these cells are scarce. The successful creation of a bioengineered tooth is achievable only when the odontogenic epithelium is reconstructed to produce a replica of natural enamel. This article discusses the untapped sources of odontogenic epithelial stem cells in humans, such as those present in the active dental lamina in postnatal life, in remnants of dental lamina (the gubernaculum cord), in the epithelial cell rests of Malassez, and in reduced enamel epithelium. The possible uses of these stem cells in regenerative medicine, not just for enamel formation, are discussed.

Canonical Wnt signaling acts synergistically on BMP9-induced osteo/odontoblastic differentiation of stem cells of dental apical papilla (SCAPs)

Dental pulp/dentin regeneration using dental stem cells combined with odontogenic factors may offer great promise to treat and/or prevent premature tooth loss. Here, we investigate if BMP9 and Wnt/β-catenin act synergistically on odontogenic differentiation. Using the immortalized SCAPs (iSCAPs) isolated from mouse apical papilla tissue, we demonstrate that Wnt3A effectively induces early osteogenic marker alkaline phosphatase (ALP) in iSCAPs, which is reduced by β-catenin knockdown. While Wnt3A and BMP9 enhance each other's ability to induce ALP activity in iSCAPs, silencing β-catenin significantly diminishes BMP9-induced osteo/odontogenic differentiation. Furthermore, silencing β-catenin reduces BMP9-induced expression of osteocalcin and osteopontin and in vitro matrix mineralization of iSCAPs. In vivo stem cell implantation assay reveals that while BMP9-transduced iSCAPs induce robust ectopic bone formation, iSCAPs stimulated with both BMP9 and Wnt3A exhibit more mature and highly mineralized trabecular bone formation. However, knockdown of β-catenin in iSCAPs significantly diminishes BMP9 or BMP9/Wnt3A-induced ectopic bone formation in vivo. Thus, our results strongly suggest that β-catenin may play an important role in BMP9-induced osteo/ondontogenic signaling and that BMP9 and Wnt3A may act synergistically to induce osteo/odontoblastic differentiation of iSCAPs. It's conceivable that BMP9 and/or Wnt3A may be explored as efficacious biofactors for odontogenic regeneration and tooth engineering.

Imperative role of dental pulp stem cells in regenerative therapies: a systematic review

Stem cells are primitive cells that can differentiate and regenerate organs in different parts of the body such as heart, bones, muscles and nervous system. This has been a field of great clinical interest with immense possibilities of using the stem cells in regeneration of human organ those are damaged due to disease, developmental defects and accident. The knowledge of stem cell technology is increasing quickly in all medical specialties and in dental field too. Stem cells of dental origin appears to hold the key to various cell-based therapies in regenerative medicine, but most avenues are in experimental stages and many procedures are undergoing standardization and validation. Long-term preservation of SHED cells or DPSC is becoming a popular consideration, similar to the banking of umbilical cord blood. Dental pulp stem cells (DPSCs) are the adult multipotent cells that reside in the cell rich zone of the dental pulp. The multipotent nature of these DPSCs may be utilized in both dental and medical applications. A systematic review of the literature was performed using various internet based search engines (PubMed, Medline Plus, Cochrane, Medknow, Ebsco, Science Direct, Hinari, WebMD, IndMed, Embase) using keywords like “dental pulp stem cells”, “regeneration”, “medical applications”, “tissue engineering”. DPSCs appears to be a promising innovation for the re-growth of tissues however, long term clinical studies need to be carried out that could establish some authentic guidelines in this perspective.

Bone morphogenetic protein-9 effectively induces osteo/odontoblastic differentiation of the reversibly immortalized stem cells of dental apical papilla

Dental pulp/dentin regeneration using dental stem cells combined with odontogenic factors may offer great promise to treat and/or prevent premature tooth loss. We previously demonstrated that bone morphogenetic protein 9 (BMP9) is one of the most potent factors in inducing bone formation. Here, we investigate whether BMP9 can effectively induce odontogenic differentiation of the stem cells from mouse apical papilla (SCAPs). Using a reversible immortalization system expressing SV40 T flanked with Cre/loxP sites, we demonstrate that the SCAPs can be immortalized, resulting in immortalized SCAPs (iSCAPs) that express mesenchymal stem cell markers. BMP9 upregulates Runx2, Sox9, and PPARγ2 and odontoblastic markers, and induces alkaline phosphatase activity and matrix mineralization in the iSCAPs. Cre-mediated removal of SV40 T antigen decreases iSCAP proliferation. The in vivo stem cell implantation studies indicate that iSCAPs can differentiate into bone, cartilage, and, to lesser extent, adipocytes upon BMP9 stimulation. Our results demonstrate that the conditionally iSCAPs not only maintain long-term cell proliferation but also retain the ability to differentiate into multiple lineages, including osteo/odontoblastic differentiation. Thus, the reversibly iSCAPs may serve as an important tool to study SCAP biology and SCAP translational use in tooth engineering. Further, BMP9 may be explored as a novel and efficacious factor for odontogenic regeneration.