Isolation and culture of dental pulp stem cells from permanent and deciduous teeth

Comparative Analysis of the Cytotoxic Effects of Modified Triple Antibiotic Hydrogel: Insights From Experimental Models

INTRODUCTION

 The effectiveness of intracanal medicaments (ICMs) in root canal therapy is critical for successful dental treatments, yet their cytotoxic effects pose significant challenges. This research uses zebrafish embryos and dental pulp stem cells (DPSCs) to identify the optimal concentration that balances antibacterial efficacy with minimal toxicity.

AIM

 This study aims to address the need for effective ICMs in dentistry by formulating and assessing the embryotoxicity and cytocompatibility of a novel carrageenan-based modified triple antibiotic paste (MTAP) hydrogel at different concentrations (1, 5, and 10 mg/mL) using a zebrafish model and cell culture assay.

MATERIALS AND METHODS

 The hydrogel was formulated by combining antibiotic solutions (ciprofloxacin, metronidazole, and amoxicillin) with carrageenan and xanthan gum. Zebrafish embryos were exposed to varying concentrations of MTAP hydrogel, chlorhexidine (CHX), calcium hydroxide (CaOH2), and plain carrageenan to assess developmental toxicity, survival rate, heart rate, hatching rate, and macrophage migration. The cytotoxicity against DPSCs was examined within a timeframe of 6, 24, and 72 hours with the use of the 3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyltetrazolium bromide (MTT) assay.

RESULTS

 The analysis revealed developmental toxicity with malformations observed at higher concentrations of MTAP hydrogel, CaOH2, and CHX medicaments, indicating potential toxicity. Significant impacts on survival, heart rate, and hatching rate were noted in the CaOH2 and CHX groups, as well as at higher MTAP hydrogel concentrations, emphasizing the importance of dosage considerations. The neutral red assay confirmed toxicity, with macrophage migration observed in CaOH2, CHX, and higher MTAP hydrogel concentrations. Lower concentrations, particularly at 1 mg/mL, showed no adverse effects on zebrafish embryos and larvae. These findings align with cell viability investigations, which demonstrated that higher antibiotic concentrations resulted in decreased cell proliferation and viability over time. Conversely, at a lower concentration of 1 mg/mL, cell proliferation notably increased after 72 hours. Plain MTAP and CHX exhibited the highest toxicity levels in the MTT assay.

CONCLUSION

 The study concludes that while higher concentrations of MTAP hydrogel exhibit toxic effects, the hydrogel at 1 mg/mL demonstrates no adverse impact on zebrafish embryos, larvae, and DPSCs. These findings underscore the necessity of optimizing ICM concentrations to balance antibacterial efficacy and minimal cytotoxicity.

Isolation and Culture of Primary Human Dental Pulp Cells-A Description of Technical and Methodological Steps to Maximise Predictability and Yield

The dental pulp has critical functions in tooth development as well as an ongoing role in promoting and maintaining the vitality of teeth. In particular, its regenerative ability allows dental tissues to be restored following damage caused by traumatic injury or caries. Regenerative endodontic procedures aim to utilise these processes to stimulate dental pulp repair in a minimally invasive manner and reduce the need for more invasive procedures such as root canal treatment. Dental pulp is a source of dental pulp cells (DPCs), which has a subpopulation of dental pulp stem cells (DPSCs), which are attractive for use in regenerative medicine due to their high proliferation rate, ability to differentiate into multiple cell types, and their preserved vitality following cryopreservation. The development of next-generation clinical therapeutics that maximise the potential of dental pulp relies on strong empirical evidence arising from in vitro experimentation. Here, we describe a modified method for the efficient isolation of primary human DPCs from sound third molar teeth for culture using an explant outgrowth method on basement membrane-coated flasks, as well as using high-resolution macro-photography to illustrate the methods. Critically, steps are taken to minimise potential physical and mechanical trauma to the cells and maximise yield. Human DPCs cultured using this method can be further expanded in cell culture flasks to facilitate their use in various in vitro experimental procedures.

Mesenchymal Stromal Cells Derived from Dental Tissues: Immunomodulatory Properties and Clinical Potential

Mesenchymal stem/stromal cells (MSCs) are multipotent cells located in different areas of the human body. The oral cavity is considered a potential source of MSCs because they have been identified in several dental tissues (D-MSCs). Clinical trials in which cells from these sources were used have shown that they are effective and safe as treatments for tissue regeneration. Importantly, immunoregulatory capacity has been observed in all of these populations; however, this function may vary among the different types of MSCs. Since this property is of clinical interest for cell therapy protocols, it is relevant to analyze the differences in immunoregulatory capacity, as well as the mechanisms used by each type of MSC. Interestingly, D-MSCs are the most suitable source for regenerating mineralized tissues in the oral region. Furthermore, the clinical potential of D-MSCs is supported due to their adequate capacity for proliferation, migration, and differentiation. There is also evidence for their potential application in protocols against autoimmune diseases and other inflammatory conditions due to their immunosuppressive capacity. Therefore, in this review, the immunoregulatory mechanisms identified at the preclinical level in combination with the different types of MSCs found in dental tissues are described, in addition to a description of the clinical trials in which MSCs from these sources have been applied.

A newly improved method of primary cell culture: Tissue block with continuous adhesion subculture in skin fibroblast

BACKGROUND

Fibroblasts (FBs) have been widely used as a typical in vitro cell model for investigating the biological processes and cell pathophysiological mechanisms. However, FBs are prone to senescence in cell culture process after several passages. Thus, a new approach to cell culture is quite required to enhance the viability of cells.

OBJECTIVE

To explore a novel method of cell culture based on skin FBs.

METHODS

Dermal tissue blocks were obtained from BALB/c neonatal mice and randomly divided into experimental group and control group. The experimental group received the newly improved culture method, namely, continuous adherence subculture of tissue block (CASTB) method; while the traditional subculture method was applied in the control group. Cells at 1st, 5th and 10th passages were collected and identified by using histological/immunohistochemical and western blot analysis. Cellular viability, proliferation, senescence and apoptosis were analyzed through application of cell growth curve, CCK-8 assay, Ki67 assay, PCNA protein analysis, β-galactosidase staining, flow cytometry and western blot analysis.

RESULTS

Cells under two culture patterns exhibited spindle/irregular shape and vimentin positive expression. With the increase of passage times, the cellular growth rate in the control group gradually decreased, but no alterations emerged from the experimental group. CASTB method remarkably promoted cell growth and proliferation. Moreover, a greatly lower apoptosis and senescence tendency appeared in the experimental group than the control group with passages increasing.

CONCLUSION

The method of CASTB is superior to traditional subculture, offering a large number of primary FBs with higher efficiency and success rate and being worth of further popularization and application.

Stem cell sources from human biological waste material: a role for the umbilical cord and dental pulp stem cells for regenerative medicine

Stem cell research with biological waste material is an area that holds promise to revolutionize treatment modalities and clinical practice. The interest in surgical remnants is increasing with time as research on human embryonic stem cells remains controversial due to legal and ethical issues. Perhaps, these restrictions are the motivation for the use of alternative mesenchymal stem cell (MSC) sources in the regenerative field. Stem cells (SCs) of Umbilical Cord (UC) and Dental Pulp (DP) have almost similar biological characteristics to other MSCs and can differentiate into a number of cell lineages with enormous potential future prospects. A concise critical observation of UC-MSCs and DP-MSCs is presented here reviewing articles from the last two decades along with other stem cell sources from different biological waste materials.

Biocompatibility of mesoporous SBA-16/hydroxyapatite nanocomposite and dentin demineralized particles on human dental pulp stem cells

In the present work, a biomaterial (SBA-16/HA) based on the growth of hydroxyapatite (HA) particles within an organized silica structure SBA-16 (Santa Barbara Amorphous-16) was developed to evaluate its application to act as a porous microenvironment promoting attachment and viability of human dental pulp stem cells of healthy deciduous teeth (SHED). First, SHED were isolated and their phenotypes were evaluated by flow cytometry. The samples of SBA-16/HA were characterized by X-ray diffraction (XRD), small and wide angle X-ray scattering (SWAXS), Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM) equipped with energy dispersive spectra detector (EDS). Afterward, cells were cultured in the eluates of the above-mentioned biomaterial aged for 24 hr, 7. and 14 days. Bio-Oss® and dentin particles are involved for comparison and cells are cultured in the eluates of these two materials also. Thiazolyl Blue Tetrazolium bromide assay-MTT (3-(4,5-Dimethylthiazol-2-yl)-2,5-Diphenyltetrazolium Bromide assay) was used for the determination of cell viability. The results obtained by all aforementioned characterization methods of SBA-16/HA, revealed a uniform spherical mesoporous structure, an intrinsic characteristic of this material. This material displayed excellent biocompatibility on SHEDs, and even proliferative potential, indicating that SBA-16/HA could potentially serve as a suitable substrate for bone regeneration. Contrary to SBA-16/HA, dentin particles showed low cytotoxicity at all time points, compared to control and Bio-Oss®groups. Our results substantiate the idea that SBA-16/HA has a beneficial effect on SHEDs, thus paving the way toward developing new material for bone replacement.

Increased proliferation and differentiation capacity of placenta-derived mesenchymal stem cells from women of median maternal age correlates with telomere shortening

Mesenchymal stem cells (MSCs) experience functional decline with systemic aging, resulting in reduced proliferation, increased senescence, and lower differentiation potential. The placenta represents a valuable source of MSCs, but the possible effect of donor age on the properties of placenta-derived mesenchymal stem cells (PDMSCs) has not been thoroughly studied. Thus, the aim of this study was to underscore the effect of maternal age on the biological characteristics and stemness properties of PDMSCs. PDMSCs were isolated from 5 donor age groups (A: 18-21, B: 22-25, C: 26-30, D:31-35 and E: ≥36 years) for comparison of morphological, proliferative and differentiation properties. The pluripotency markers NANOG, OCT4, and SSEA4, as well as multipotency and differentiation markers, showed higher expression in PDMSCs from mothers aged 22-35 years, with up to a 7-fold increase in adipogenesis. Cumulative population doubling, cell growth curves, and colony-forming unit-fibroblast assays revealed higher self-renewal ability in donors 26-30 years old. An increase in the proliferative characteristics of PDMSCs correlated with increased telomere shortening, suggesting that shorter telomere lengths could be related to cellular division rather than aging. A clear understanding of the effect of maternal age on MSC regenerative potential will assist in increasing the effectiveness of future cell therapies.

Chondrogenic Potential of Dental-Derived Mesenchymal Stromal Cells

The field of tissue engineering has revolutionized the world in organ and tissue regeneration. With the robust research among regenerative medicine experts and researchers, the plausibility of regenerating cartilage has come into the limelight. For cartilage tissue engineering, orthopedic surgeons and orthobiologists use the mesenchymal stromal cells (MSCs) of various origins along with the cytokines, growth factors, and scaffolds. The least utilized MSCs are of dental origin, which are the richest sources of stromal and progenitor cells. There is a paradigm shift towards the utilization of dental source MSCs in chondrogenesis and cartilage regeneration. Dental-derived MSCs possess similar phenotypes and genotypes like other sources of MSCs along with specific markers such as dentin matrix acidic phosphoprotein (DMP) -1, dentin sialophosphoprotein (DSPP), alkaline phosphatase (ALP), osteopontin (OPN), bone sialoprotein (BSP), and STRO-1. Concerning chondrogenicity, there is literature with marginal use of dental-derived MSCs. Various studies provide evidence for in-vitro and in-vivo chondrogenesis by dental-derived MSCs. With such evidence, clinical trials must be taken up to support or refute the evidence for regenerating cartilage tissues by dental-derived MSCs. This article highlights the significance of dental-derived MSCs for cartilage tissue regeneration.

Isolation, Characterization, and Differentiation of Stem Cells From Various Dental Sources: An In Vitro Study

Aim:

The aim of the current study was to isolate stem cells from various dental sources such as dental pulp, periodontal ligament (PDL), and apical papilla, and to characterize stem cells by staining for the presence/absence of specific surface markers and also to differentiate stem cells into osteogenic, chondrogenic, and adipogenic cell lineages by exposing them to specific growth factors under the ideal conditions.

Materials and Methods:

A total of 117 samples were included in the study, consisting of 30 pulp, 50 gingival, 35 PDL, and 2 apical papilla samples. The pulp was extirpated and transported to the Central Research Laboratory. Gingival connective tissue was collected from the participants undergoing any crown lengthening procedure or any gingivectomy procedure from the Department of Periodontology. A similar procedure was also followed for apical papilla and PDL. Isolation was done followed by the identification of the cells by immunocytochemistry using different markers. Once the identity of cells was confirmed, these cells were treated with different culture media to attain 70% to 100% confluency. Then the medium was replaced with a conditioning medium containing specific growth factors for differentiation into osteogenic, chondrogenic, and adipogenic cell lineages.

Result:

In our study, the number of samples collected and processed was 117. The isolation rate of stem cells from the above-collected samples was 70%. Statistical analysis—no statistical analysis was done as there was no variability expected.

Conclusion:

Our study showed that stem cells could be isolated, differentiated, and characterized from different dental sources.

Ultrasonic techniques to obtain dental pulp from impacted third molars

Background

In the dental clinic impacted teeth are frequent findings, especially upper and lower third molars, leading to their exodontia. Among surgical techniques piezosurgery is advantageous for delicate structures in the oral cavity. Extracted teeth, usually discarded, have been revalued as biological material, providing living tissues with possible applications in regenerative dentistry. The aim was to compare cross-section methods of upper included third molars by ultrasonic piezoelectric technique to obtain dental pulp, with diamond-coated tip (DT) against titanium nitride-coated tip (TN), according to the pulp tissue cell viability and the section surface characteristics.

Material and Methods

Patients attending dental consultation were evaluated. Upper third molars (n= 24) were avulsed from 15 patients with exodontia indication, age 18-26 years old, who agreed to participate of the study. Third molars were cross-sectioned at amelocemental junction level with piezoelectric device using DT or TN inserts. Pulps were mechanic and enzymatically treated, and tissue viability determined by Trypan Blue test. Sectioned teeth were visualized using Scanning Electron Microscope (SEM). Ethical principles of biomedical research were respected; all patients gave their informed consent.

Results

Viability of pulp tissue was 84.71% not associated to sex (p= 0.141) nor to teeth position, upper right third molar or upper left third molar (p= 0.580). According to the insert used, pulp tissue viability was 85.21% with TN, similar to 84.00% with DT (p= 0.611). By SEM, cut performed by TN insert showed smooth and uniform surfaces, while DT insert surfaces were irregular, porous, with fissures.

Conclusions

Piezosurgery applied to cross-section upper third molars with both types of inserts showed differences in the cut surfaces but similar effectiveness regarding preservation of pulp tissue with high viability, thus, they could be allocated for further cellular developments. Key words:Impacted teeth, third molars, piezosurgery, regenerative dentistry.

The Effect of Age and Type of Media on Growth Kinetics of Human Amniotic Fluid Stem Cells

Aim: This study compared growth kinetics of human amniotic fluid stem cells (hAFSCs) in different maternal age groups and two different media of AmnioMAX and Dulbecco's modified Eagle's medium (DMEM). Materials and Methods: Three milliliters of amniotic fluid (AF) was provided from 16 pregnant women who were referred for amniocentesis from 16 to 18 weeks of gestation. Mothers were divided to 20-29 (n = 5), 30-39 (n = 5) and 40-49 (n = 6) years old age groups. AF was immediately centrifuged and the cell pellet was cultured. Cells were characterized morphologically, by flow cytometry and for osteogenic and adipogenic inductions. Population doubling time (PDT) and growth kinetics were determined. AFSCs cultured in AmnioMAX were compared in various age groups. A comparison of growth kinetics of AFSCs cultured in AmnioMAX and DMEM from 40 to 49 years old pregnant women was undertaken. Results: AFSCs were adherent to culture flasks and were spindle shape, and positive for osteogenic and adipogenic inductions and for expression of CD73, CD90 and CD105 markers, but negative for CD34 and CD45. PDT among 20-29, 30-39, and 40-49 years old women was 30.9, 38.3, and 43.9 hours, respectively showing a higher cell proliferation in younger ages. When comparing AmnioMAX and DMEM, PDT was 53 and 96.9 hours, respectively denoting to a higher cell proliferation in AmnioMAX. Conclusions: Higher proliferation and plasticity of hAFSCs were noted in AmnioMAX and in younger mothers' samples. These findings can be added to the literature and open a new avenue in regenerative medicine, when hAFSCs are targeted for cell therapy purposes.

Therapeutic Functions of Stem Cells from Oral Cavity: An Update

Adult stem cells have been developed as therapeutics for tissue regeneration and immune regulation due to their self-renewing, differentiating, and paracrine functions. Recently, a variety of adult stem cells from the oral cavity have been discovered, and these dental stem cells mostly exhibit the characteristics of mesenchymal stem cells (MSCs). Dental MSCs can be applied for the replacement of dental and oral tissues against various tissue-damaging conditions including dental caries, periodontitis, and oral cancers, as well as for systemic regulation of excessive inflammation in immune disorders, such as autoimmune diseases and hypersensitivity. Therefore, in this review, we summarized and updated the types of dental stem cells and their functions to exert therapeutic efficacy against diseases.