A Review of Stem Cell Attributes Derived from the Oral Cavity.

Oral cavity stem cells (OCSCs) have been the focus of intense scientific efforts due to their accessibility and stem cell properties. The present work aims to compare the different characteristics of 6 types of dental stem cells derived from the oral cavity: dental pulp stem cells (DPSC), stem cells from human exfoliated deciduous teeth (SHED), periodontal ligament stem cells (PDLSC), stem cells from the apical papilla (SCAP), bone marrow mesenchymal stem cells (BMSC), and gingival mesenchymal stem cells (GMSC). Using immunofluorescence and real-time polymerase chain reaction techniques, we analysed the cells for stem cell, differentiation, adhesion, and extracellular matrix markers; the ability to proliferate in vitro; and multilineage differentiation potential. Markers such as vimentin, CD44, alkaline phosphatase, CD146, CD271, CD49f, Oct 3/4, Sox 9, FGF7, nestin, and BMP4 showed significant differences in expression levels, highlighting the heterogeneity and unique characteristics of each cell type. At the same time, we confirmed that all cell types successfully differentiated into osteogenic, chondrogenic, or adipose lineages, with different readiness. In conclusion, our study reveals the distinct properties and potential applications of various dental-derived stem cells. These findings contribute to a deeper understanding of OCSCs and their significance in future clinical applications.

Exosomes miR-92a-3p from human exfoliated deciduous teeth inhibits periodontitis progression via the KLF4/PI3K/AKT pathway.

BACKGROUND: Periodontitis is a chronic inflammatory disease mediated by dysbiosis of the oral microflora, resulting in the destruction of periodontal tissue. Increasing evidence suggested that mesenchymal stem cell (MSCs) and exosomes derived from MSCs play a critical role in periodontal tissue regeneration. However, whether stem cells from exfoliated deciduous teeth (SHED)-secreted exosomes can improve the therapeutic potential of periodontitis is largely unknown. OBJECTIVE: Here, we aim to evaluate the effect of SHED-exosomes on inflammation, apoptosis and osteogenic differentiation in periodontitis. METHODS: The periodontitis cell model was constructed by stimulating periodontal ligament stem cells (PDLSCs) with lipopolysaccharide (LPS), and the periodontitis rats were established by ligation. RESULTS: First, we isolated exosomes from the SHED, and we figured out that exosomes secreted by SHED were enriched in miR-92a-3p and the exosomes enhanced proliferation and osteogenic differentiation and reduced apoptosis and inflammatory responses in PDLSCs. In addition, we found that SHED-exosomes alleviated inflammatory effect and elevated the expression of osteogenic-related genes in periodontitis rat model. Moreover, miR-92a-3p targeted downstream Krüppel-Like Transcription Factor 4 (KLF4) and regulated the PI3K/AKT pathway. Finally, our data indicated that upregulation of KLF4 or activation of PI3K/AKT by 740Y-P counteracted the inhibitory effect of SHED-exosomes on periodontitis progression. CONCLUSION: Taken together, our finding revealed that exosomal miR-92a-3p derived from SHED contributed to the alleviation of periodontitis development and progression through inactivating the KLF4/PI3K/AKT signaling pathway, which may provide a potential target for the treatment of periodontitis.

"Biological responses of two calcium-silicate-based cements on a tissue-engineered 3D organotypic deciduous pulp analogue".

OBJECTIVES: The biological responses of MTA and Biodentine™ has been assessed on a three-dimensional, tissue-engineered organotypic deciduous pulp analogue. METHODS: Human endothelial (HUVEC) and dental mesenchymal stem cells (SHED) at a ratio of 3:1, were incorporated into a collagen I/fibrin hydrogel; succeeding Biodentine™ and MTA cylindrical specimens were placed in direct contact with the pulp analogue 48 h later. Cell viability/proliferation and morphology were evaluated through live/dead staining, MTT assay and Scanning Electron Microscopy (SEM), and expression of angiogenic, odontogenic markers through real time PCR. RESULTS: Viable cells dominated at day 3 after treatment presenting typical morphology, firmly attached within the hydrogel structures, as shown by live/dead staining and SEM images. MTT assay at day 1 presented a significant increase of cell proliferation in Biodentine™ group. Real-time PCR showed significant upregulation of odontogenic markers DSPP, BMP-2 (day 3,6), RUNX2, ALP (day 3) in contact with Biodentine™ compared to MTA and the control, whereas MTA promoted significant upregulation of DSPP, BMP-2, RUNX2, Osterix (day 3) and ALP (day 6) compared to the control. MSX1 presented downregulation in both experimental groups. Expression of angiogenic markers VEGFa and ANGPT-1 at day 3 was significantly upregulated in contact with Biodentine™ and MTA respectively, while the receptors VEGFR1, VEGFR2 and Tie-2, as well as PECAM-1 were downregulated. SIGNIFICANCE: Both calcium silicate-based materials are biocompatible and exert positive angiogenic and odontogenic effects, although Biodentine™ during the first days of culture, seems to induce higher cell proliferation and provoke a more profound odontogenic and angiogenic response from SHED.

Advancements in Spinal Cord Injury Repair: Insights from Dental-Derived Stem Cells.

Spinal cord injury (SCI), a prevalent and disabling neurological condition, prompts a growing interest in stem cell therapy as a promising avenue for treatment. Dental-derived stem cells, including dental pulp stem cells (DPSCs), stem cells from human exfoliated deciduous teeth (SHED), stem cells from the apical papilla (SCAP), dental follicle stem cells (DFSCs), are of interest due to their accessibility, minimally invasive extraction, and robust differentiating capabilities. Research indicates their potential to differentiate into neural cells and promote SCI repair in animal models at both tissue and functional levels. This review explores the potential applications of dental-derived stem cells in SCI neural repair, covering stem cell transplantation, conditioned culture medium injection, bioengineered delivery systems, exosomes, extracellular vesicle treatments, and combined therapies. Assessing the clinical effectiveness of dental-derived stem cells in the treatment of SCI, further research is necessary. This includes investigating potential biological mechanisms and conducting Large-animal studies and clinical trials. It is also important to undertake more comprehensive comparisons, optimize the selection of dental-derived stem cell types, and implement a functionalized delivery system. These efforts will enhance the therapeutic potential of dental-derived stem cells for repairing SCI.

Modeling Lysosomal Storage Disorders in an Innovative Way: Establishment and Characterization of Stem Cell Lines from Human Exfoliated Deciduous Teeth of Mucopolysaccharidosis Type II Patients.

Among the many lysosomal storage disorders (LSDs) that would benefit from the establishment of novel cell models, either patient-derived or genetically engineered, is mucopolysaccharidosis type II (MPS II). Here, we present our results on the establishment and characterization of two MPS II patient-derived stem cell line(s) from deciduous baby teeth. To the best of our knowledge, this is the first time a stem cell population has been isolated from LSD patient samples obtained from the dental pulp. Taking into account our results on the molecular and biochemical characterization of those cells and the fact that they exhibit visible and measurable disease phenotypes, we consider these cells may qualify as a valuable disease model, which may be useful for both pathophysiological assessments and in vitro screenings. Ultimately, we believe that patient-derived dental pulp stem cells (DPSCs), particularly those isolated from human exfoliated deciduous teeth (SHEDs), may represent a feasible alternative to induced pluripotent stem cells (iPSCs) in many labs with standard cell culture conditions and limited (human and economic) resources.

Ozone Treatment for the Management of Caries in Primary Dentition: A Systematic Review of Clinical Studies.

Dental caries in children is a frequent and debilitating condition, whose management is often challenging. The aim of this systematic review was to investigate the effectiveness of ozone applications for the treatment of caries in primary dentition. According to PRISMA guidelines, a systematic literature search was performed up to 6 January 2024. Clinical studies using ozone to treat caries of deciduous teeth were considered for inclusion. Out of the 215 records retrieved, seven studies were eventually included in the review, all of which used gaseous ozone. Four studies were judged at high risk of bias, two at low risk, and one of some concerns. The great heterogeneity of designs, outcomes, and protocols made it impossible to conduct a meta-analysis. Despite some limitations, the evidence yielded by the included studies suggests that ozone application, regardless of the protocol applied, is comparable to other interventions in terms of clinical outcomes and anti-bacterial activity, with no reported adverse effects and good patient acceptance. Therefore, ozone application may be a non-invasive approach to treat caries in primary dentition, especially in very young and poorly cooperative patients. Further standardized and rigorous studies are, however, needed to identify the best clinical protocols for this specific field.

An Exploratory Investigation of Organic Chemicals Detected in Baby Teeth: Differences in Children with and without Autism.

Autism spectrum disorder (ASD) is a behaviorally defined neurodevelopmental disorder characterized by deficits in language, communication, and social function with an estimated prevalence rate of between 1 in 30 and 44 U.S. births. Gene/environment (G × E) interactions are widely regarded as the most probable explanation for idiopathic ASD, especially because some genes are selectively targeted by various environmental xenobiotics. Because deciduous teeth are a likely biomarker of in utero exposure, the present study investigated if the quantity of chemicals found in deciduous teeth differs between children with and without ASD. Twenty-two deciduous teeth from children with ASD and 20 teeth from typically developed children were prepared and analyzed using THE Two-Dimensional Gas Chromatography Time-of-Flight Mass Spectrometer (GC × GC-TOF MS) with ChromaTOF version 23H2 software and Agilent 7890 gas chromatograph. The autism sample had significantly more chemicals in their teeth than the typical developing sample (99.4 vs. 80.7, respectively) (p < 0.0001). The majority of chemicals were identified as phthalates, plasticizers, pesticides, preservatives, or intermediary solvents used in the production of fragranced personal care or cleaning products or flavoring agents in foods. The known toxic analytes reported in this study are likely biomarkers of developmental exposure. Why there were greater concentrations of toxic chemicals in the teeth that came from children with ASD is unclear. A further understanding of the cavalcade of multiple biological system interactions (Interactome) could help with future efforts to reduce risks. Notwithstanding, the avoidance of pesticides, plastics, and scented personal care products may be warranted under the precautionary principle rule.

Apoptotic Vesicles Modulate Endothelial Metabolism and Ameliorate Ischemic Retinopathy via PD1/PDL1 Axis.

Pathological angiogenesis with subsequent disturbed microvascular remodeling is a major cause of irreversible blindness in a number of ischemic retinal diseases. The current anti-vascular endothelial growth factor therapy can effectively inhibit angiogenesis, but it also brings significant side effects. The emergence of stem cell derived extracellular vesicles provides a new underlining strategy for ischemic retinopathy. Apoptotic vesicles (apoVs) are extracted from stem cells from human exfoliated deciduous teeth (SHED). SHED-apoVs are delivered into the eyeballs of oxygen-induced retinopathy (a most common model of angiogenic retinal dieseases) mice through intravitreal injection. The retinal neovascularization and nonperfusion area, vascular structure, and density changes are observed during the neovascularization phase (P17) and vascular remodeling phase (P21), and visual function is measured. The expression of extracellular acidification rate and lactic acid testing are used to detect endothelial cells (ECs) glycolytic activity. Furthermore, lentivirus and neutralizing antibody are used to block PD1-PDL1 axis, investigating the effects of SHED-apoVs on glycolysis and angiogenic activities. This work shows that SHED-apoVs are taken up by ECs and modulate the ECs glycolysis, leading to the decrease of abnormal neovessels and vascular remodeling. Furthermore, it is found that, at the molecular level, apoVs-carried PD1 interacts with PDL1 on hypoxic ECs to regulate the angiogenic activation. SHED-apoVs inhibit pathological angiogenesis and promote vascular remodeling in ischemic retinopathy partially by modulating ECs glycolysis through PD1/PDL1 axis. This study provides a new potential strategy for the clinical treatment of pathological retinal neovascularization.

Quantified retrospective biomonitoring of fetal and infant elemental exposure using LA-ICP-MS analysis of deciduous dentin in three contrasting human cohorts.

BACKGROUND: Spatial elemental analysis of deciduous tooth dentin combined with odontochronological estimates can provide an early life (in utero to ~2 years of age) history of inorganic element exposure and status. OBJECTIVE: To demonstrate the importance of data normalization to a certified reference material to enable between-study comparisons, using populations with assumed contrasting elemental exposures. METHODS: We used laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) of dentin to derive a history of elemental composition from three distinct cohort studies: a present day rural cohort, (the New Hampshire Birth Cohort Study (NHBCS; N = 154)), an historical cohort from an urban area (1958-1970), (the St. Louis Baby Tooth Study (SLBT; N = 78)), and a present-day Nigerian cohort established to study maternal HIV transmission (Dental caries and its association with Oral Microbiomes and HIV in young children-Nigeria (DOMHaIN; N = 31)). RESULTS: We report Li, Al, Mn, Cu, Zn, Sr, Ba and Pb concentrations (µg/g) and qualitatively examine As, Cd and Hg across all three cohorts. Rates of detection were highest, both overall and for each cohort individually, for Zn, Sr, Ba and Li. Zinc was detected in 100% of samples and was stably present in teeth at a concentration range of 64 - 86 µg/g. Mercury, As and Cd detection rates were the lowest, and had high variability within individual ablated spots. We found the highest concentrations of Pb in the pre- and postnatal dentin of the SLBT cohort, consistent with the prevalent use of Pb as an additive to gasoline prior to 1975. The characteristic decline in Mn after the second trimester was observed in all cohorts. IMPACT: Spatially resolved elemental analysis of deciduous teeth combined with methods for estimating crown formation times can be used to reconstruct an early-life history of elemental exposure inaccessible via other biomarkers. Quantification of data into absolute values using an external standard reference material has not been conducted since 2012, preventing comparison between studies, a common and highly informative component of epidemiology. We demonstrate, with three contrasting populations, that absolute quantification produces data with the lowest variability, compares well with available data and recommends that future tooth biomarker studies report data in this way.

Molecular insights into the proteomic composition of porcine treated dentin matrix.

Background: Human-treated dentin matrix (hTDM) has recently been studied as a natural extracellular matrix-based biomaterial for dentin pulp regeneration. However, porcine-treated dentin matrix (pTDM) is a potential alternative scaffold due to limited availability. However, there is a dearth of information regarding the protein composition and underlying molecular mechanisms of pTDM.Methods: hTDM and pTDM were fabricated using human and porcine teeth, respectively, and their morphological characteristics were examined using scanning electron microscopy. Stem cells derived from human exfoliated deciduous teeth (SHEDs) were isolated and characterized using flow cytometry and multilineage differentiation assays. SHEDs were cultured in three-dimensional environments with hTDM, pTDM, or biphasic hydroxyapatite/tricalcium phosphate. The expression of odontogenesis markers in SHEDs were assessed using real-time polymerase chain reaction and immunochemical staining. Subsequently, SHEDs/TDM and SHEDs/HA/TCP complexes were transplanted subcutaneously into nude mice. The protein composition of pTDM was analyzed using proteomics and compared to previously published data on hTDM.Results: pTDM and hTDM elicited comparable upregulation of odontogenesis-related genes and proteins in SHEDs. Furthermore, both demonstrated the capacity to stimulate root-related tissue regeneration in vivo. Proteomic analysis revealed the presence of 278 protein groups in pTDM, with collagens being the most abundant. Additionally, pTDM and hTDM shared 58 identical proteins, which may contribute to their similar abilities to induce odontogenesis. Conclusions: Both hTDM and pTDM exhibit comparable capabilities in inducing odontogenesis, potentially owing to their distinctive bioactive molecular networks.

Persistent deciduous teeth: Association of prevalence with breed, breed size and body weight in pure-bred client-owned dogs in the United States.

Dogs use their teeth for a multitude of tasks and, as such, it is vital for their health and wellbeing that their oral health is maintained. Persistent deciduous teeth (PDT), those that fail to fall out at the appropriate time, are associated with malocclusion (misaligned bite), soft tissue trauma and increased risk of periodontal disease. The objective of the current study was to perform a retrospective analysis of veterinary medical data to understand the effect of dog breed size, dog breed and body weight on prevalence of PDT. Medical records collected from almost 3 million dogs visiting a chain of veterinary hospitals across the United States over a 5-year period showed an overall prevalence of 7% for PDT, the data represented 60 breeds with extra-small breeds (<6.5 kg) showing significantly higher prevalence (15%) than all other breed sizes (P < 0.001). Statistical modelling of extra-small, small and medium-small breed sizes showed that those on Wellness Plans or that had not received a dental prophylaxis for at least two years had significantly increased odds of PDT being detected (Odds ratio 2.72-3.2 and 2.17-3.36 respectively, P < 0.0001). Dogs with a below ideal body condition score had a decreased odds of PDT (Odds ratio 0.57-0.89, P < 0.0001) whereas those above ideal had an increased odds (Odds ratio 1.11-1.60, P < 0.0001). The findings from this extensive dataset highlight the importance of regular veterinarian examinations to identify and remove PDT, helping to avoid increasing the risk of associated issues such as periodontal disease and malocclusion.

Protective Mechanism of Stem Cells from Human Exfoliated Deciduous Teeth in Treating Spinal Cord Injury.

Spinal cord injury (SCI) induces devastating permanent deficits. Recently, cell transplantation therapy has become a notable treatment for SCI. Although stem cells from human exfoliated deciduous teeth (SHED) are an attractive therapy, their precise mechanism of action remains to be elucidated. In this study, we explored one of the neuroprotective mechanisms of SHED treatment at the subacute stage after SCI. We used a rat clip compression SCI model. The animals were randomly divided into three groups: SCI, SCI + phosphate-buffered saline (PBS), and SCI + SHED. The SHED or PBS intramedullary injection was administered immediately after SCI. After SCI, we explored the effects of SHED on motor function, as assessed by the Basso-Beattie-Bresnahan score and the inclined plane method, the signal transduction pathway, especially the Janus kinase (JAK) and the signal transducer and activator of transcription 3 (STAT3) pathway, the apoptotic pathway, and the expression of neurocan, one of the chondroitin sulfate proteoglycans. SHED treatment significantly improved functional recovery from Day 14 relative to the controls. Western blot analysis showed that SHED significantly reduced the expression of glial fibrillary acidic protein (GFAP) and phosphorylated STAT3 (p-STAT3) at Tyr705 on Day 10 but not on Day 5. However, SHED had no effect on the expression levels of Iba-1 on Days 5 or 10. Immunohistochemistry revealed that p-STAT3 at Tyr705 was mainly expressed in GFAP-positive astrocytes on Day 10 after SCI, and its expression was reduced by administration of SHED. Moreover, SHED treatment significantly induced expression of cleaved caspase 3 in GFAP-positive astrocytes only in the epicenter lesions on Day 10 after SCI but not on Day 5. The expression of neurocan was also significantly reduced by SHED injection on Day 10 after SCI. Our results show that SHED plays an important role in reducing astrogliosis and glial scar formation between Days 5 and 10 after SCI, possibly via apoptosis of astrocytes, ultimately resulting in improvement in neurological functions thereafter. Our data revealed one of the neuroprotective mechanisms of SHED at the subacute stage after SCI, which improved functional recovery after SCI, a serious condition.

Stem cells derived from human exfoliated deciduous teeth-based media in a rat root resorption model.

OBJECTIVE: Root resorption may occur during orthodontic treatment. Herein, we investigated the effect of a culture supernatant of stem cells derived from human exfoliated deciduous teeth on root resorption. DESIGN: Twelve 8-week-old male Sprague-Dawley rats were used, and their maxillary first molars were pulled with excessive orthodontic force to induce root resorption. On days 1 and 7 after traction initiation, stem cells derived from human exfoliated deciduous teeth and alpha minimum essential medium (control group) were administered. After 14 days, the maxillary bone was evaluated for tooth movement. The expression of osteoprotegerin, receptor activator of nuclear factor κB ligand, tumor necrosis factor α, interleukin 1ß, interleukin 6, and interleukin 17 was evaluated on the compression side and tension side. RESULTS: No significant difference in tooth movement was observed between the two groups. Root resorption decreased in the group administered the culture supernatant compared with in the control. Immunohistochemical staining revealed increased osteoprotegerin expression and decreased receptor activators for nuclear factor κB ligand, tumor necrosis factor α, interleukin 1ß, interleukin 6, and interleukin 17 on the compression side and tension side. CONCLUSIONS: Administration of stem cells derived from human exfoliated deciduous teeth affected the expression of osteoprotegerin, receptor activator of nuclear factor κB ligand, tumor necrosis factor α, interleukin 1ß, interleukin 6 and interleukin 17; hence, these stem cells may inhibit root resorption by regulating their expression.

19th Century Deciduous Tooth Boxes from France and Belgium.

An encounter 50 years ago led to an interesting collection of tooth boxes. This paper will highlight many of those unique treasures emanating from Northwestern Europe.

Stem Cells Derived from Human Exfoliated Deciduous Teeth Functional Assessment: Exploring the Changes of Free Fatty Acids Composition during Cultivation.

The metabolic regulation of stemness is widely recognized as a crucial factor in determining the fate of stem cells. When transferred to a stimulating and nutrient-rich environment, mesenchymal stem cells (MSCs) undergo rapid proliferation, accompanied by a change in protein expression and a significant reconfiguration of central energy metabolism. This metabolic shift, from quiescence to metabolically active cells, can lead to an increase in the proportion of senescent cells and limit their regenerative potential. In this study, MSCs from human exfoliated deciduous teeth (SHEDs) were isolated and expanded in vitro for up to 10 passages. Immunophenotypic analysis, growth kinetics, in vitro plasticity, fatty acid content, and autophagic capacity were assessed throughout cultivation to evaluate the functional characteristics of SHEDs. Our findings revealed that SHEDs exhibit distinctive patterns of cell surface marker expression, possess high self-renewal capacity, and have a unique potential for neurogenic differentiation. Aged SHEDs exhibited lower proliferation rates, reduced potential for chondrogenic and osteogenic differentiation, an increasing capacity for adipogenic differentiation, and decreased autophagic potential. Prolonged cultivation of SHEDs resulted in changes in fatty acid composition, signaling a transition from anti-inflammatory to proinflammatory pathways. This underscores the intricate connection between metabolic regulation, stemness, and aging, crucial for optimizing therapeutic applications.

Effects of LED curing light on silver diamine fluoride penetration into dentin.

This ex-vivo study investigated the effect of a light-emitting diode (LED) curing light on the depth of penetration of Silver Diamine Fluoride (SDF) into carious lesions. Twenty-four primary teeth with untreated caries lesions were allocated into groups and treated within 5 min after extraction: (1) n = 6 treated for 1 min with one drop of SDF followed by 10 sec rinse with tap water, (2) n = 6 treated for 10 sec with one drop of SDF and exposed to LED light for 20 sec (30 sec total SDF exposure) followed by 10 sec rinse with tap water, (3) n = 6 treated for 10 sec with one drop of SDF followed by a 10 sec rinse with tap water, (4) n = 3 untreated, and (5) n = 3 untreated but exposed to LED light for 20 sec. Samples were prepared, embedded, sectioned and silver penetration was measured using backscattered electron imaging in the scanning electron microscope and energy-dispersive X-ray spectroscopy analysis. Results were expressed as the average relative depth of penetration (%) = Ag depth/lesion depth × 100 from 5 sites in each lesion. Group means were compared using mixed model analysis. Mean ± standard deviation (SD) penetration was: 86.4 ± 20.7% in Group 1, 94.3 ± 13.7% in Group 2, and 26.7 ± 13.9% in Group 3. Groups 1 and 2 were statistically similar and different from Group 3 (p < 0.001). Groups 4 and 5 had no silver present. Use of LED light for 20 sec after 10 sec SDF application appears to facilitate silver penetration, similar to a 1 min SDF application. Clinical studies are needed to define the role of silver penetration in sustained caries arrest.

Stemness maintenance of stem cells derived from human exfoliated deciduous teeth (SHED) in 3D spheroid formation through the TGF-ß/Smad signaling pathway.

Mesenchymal stem cells (MSCs) have shown great potential as important therapeutic tools for dental pulp tissue engineering, with the maintenance and enhancement of their stemness being crucial for successful therapeutic application in vivo and three-dimensional (3D) spheroid formation considered a reliable technique for enhancing their pluripotency. Human exfoliated deciduous tooth stem cells (SHED) were cultured in a low attachment plate to form aggregates for five days. Then, the resulting spheroids were analyzed for pluripotent marker expression, paracrine secretory function, proliferation, signaling pathways involved, and distribution of key proteins within the spheroids. The results indicated that 3D spheroid formation significantly increased the activation of the transforming growth factor beta (TGF-ß)/Smad signaling pathway and upregulated the secretion and mRNA expression levels of TGF-ß, which in turn enhanced the expression of pluripotency markers in SHED spheroids. The activation of the TGF-ß/Smad signaling pathway through 3D spheroid formation was found to preserve the stemness properties of SHED. Thus, understanding the mechanisms behind pluripotency maintenance of SHED culture through 3D spheroid formation could have implications for the therapeutic application of MSCs in regenerative medicine and tissue engineering.

Comparative analysis of DNA preservation in permanent and deciduous teeth of adults and non-adults: Implications for archaeological and forensic research.

This study investigates the preservation of DNA in different categories of teeth, including permanent and deciduous, fully developed and not fully developed, in both adults and non-adults. Teeth were sampled from a modern-era cemetery in Ljubljana, Slovenia. DNA extraction was performed using a full demineralisation protocol. DNA quantity and quality were assessed using qPCR analyses, and autosomal STR typing was conducted to verify genetic profiles. Results revealed significant differences in DNA preservation among various tooth categories. Fully developed permanent teeth of adults exhibited the highest DNA yields, attributed to their fully developed roots and thicker cementum, which is rich in DNA. Deciduous teeth, with thinner enamel and cementum, showed lower DNA preservation regardless of developmental stage. Non-adult teeth generally yielded less DNA compared to adults, even when considering only fully developed permanent teeth, indicating factors beyond developmental stage. These findings suggest that, in archaeological and forensic contexts, researchers should prioritize fully developed permanent teeth for DNA analysis due to their superior preservation. Additionally, this study underscores the importance of considering tooth type and developmental stage when selecting samples for genetic analysis in cases where petrous bone is unavailable, expanding our understanding of DNA preservation in human remains.

SHED-derived exosomes attenuate trigeminal neuralgia after CCI of the infraorbital nerve in mice via the miR-24-3p/IL-1R1/p-p38 MAPK pathway.

BACKGROUND: Microglial activation in the spinal trigeminal nucleus (STN) plays a crucial role in the development of trigeminal neuralgia (TN). The involvement of adenosine monophosphate-activated protein kinase (AMPK) and N-methyl-D-aspartate receptor 1 (NMDAR1, NR1) in TN has been established. Initial evidence suggests that stem cells from human exfoliated deciduous teeth (SHED) have a potential therapeutic effect in attenuating TN. In this study, we propose that SHED-derived exosomes (SHED-Exos) may alleviate TN by inhibiting microglial activation. This study sought to assess the curative effect of SHED-Exos administrated through the tail vein on a unilateral infraorbital nerve chronic constriction injury (CCI-ION) model in mice to reveal the role of SHED-Exos in TN and further clarify the potential mechanism. RESULTS: Animals subjected to CCI-ION were administered SHED-Exos extracted by differential ultracentrifugation. SHED-Exos significantly alleviated TN in CCI mice (increasing the mechanical threshold and reducing p-NR1) and suppressed microglial activation (indicated by the levels of TNF-α, IL-1ß and IBA-1, as well as p-AMPK) in vivo and in vitro. Notably, SHED-Exos worked in a concentration dependent manner. Mechanistically, miR-24-3p-upregulated SHED-Exos exerted a more significant effect, while miR-24-3p-inhibited SHED-Exos had a weakened effect. Bioinformatics analysis and luciferase reporter assays were utilized for target gene prediction and verification between miR-24-3p and IL1R1. Moreover, miR-24-3p targeted the IL1R1/p-p38 MAPK pathway in microglia was increased in CCI mice, and participated in microglial activation in the STN. CONCLUSIONS: miR-24-3p-encapsulated SHED-Exos attenuated TN by suppressing microglial activation in the STN of CCI mice. Mechanistically, miR-24-3p blocked p-p38 MAPK signaling by targeting IL1R1. Theoretically, targeted delivery of miR-24-3p may offer a potential strategy for TN.