The Effectiveness of Calcium Phosphates in the Treatment of Dentinal Hypersensitivity: A Systematic Review.

Dentin hypersensitivity (DH) pain is a persistent clinical problem, which is a common condition known to affect patients' quality of life (QoL), but no treatment has ever been agreed upon. Calcium phosphates, available in different forms, have properties that allow sealing the dentinal tubules, which may relieve dentin hypersensitivity. The aim of this systematic review is to evaluate the ability of different formulations of calcium phosphate to reduce dentin hypersensitivity pain level in clinical studies. The inclusion criterion was as follows: clinical randomized controlled studies using calcium phosphates in treating dentin hypersensitivity. In December 2022, three electronic databases (Pubmed, Cochrane and Embase) were searched. The search strategy was performed according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. The bias assessment risks results were carried out using the Cochrane Collaboration tool. A total of 20 articles were included and analyzed in this systematic review. The results show that calcium phosphates have properties that reduce DH-associated pain. Data compilation showed a statistically significant difference in DH pain level between T0 and 4 weeks. This VAS level reduction is estimated at about -2.5 compared to the initial level. The biomimetic and non-toxic characteristics of these materials make them a major asset in treating dentin hypersensitivity.

A critical analysis of research methods and experimental models to study pulpitis.

Pulpitis is the inflammatory response of the dental pulp to a tooth insult, whether it is microbial, chemical, or physical in origin. It is traditionally referred to as reversible or irreversible, a classification for therapeutic purposes that determines the capability of the pulp to heal. Recently, new knowledge about dental pulp physiopathology led to orientate therapeutics towards more frequent preservation of pulp vitality. However, full adoption of these vital pulp therapies by dental practitioners will be achieved only following better understanding of cell and tissue mechanisms involved in pulpitis. The current narrative review aimed to discuss the contribution of the most significant experimental models developed to study pulpitis. Traditionally, in vitro two (2D)- or three (3D)-dimensional cell cultures or in vivo animal models were used to analyse the pulp response to pulpitis inducers at cell, tissue or organ level. In vitro, 2D cell cultures were mainly used to decipher the specific roles of key actors of pulp inflammation such as bacterial by-products, pro-inflammatory cytokines, odontoblasts or pulp stem cells. However, these simple models did not reproduce the 3D organisation of the pulp tissue and, with rare exceptions, did not consider interactions between resident cell types. In vitro, tissue/organ-based models were developed to better reflect the complexity of the pulp structure. Their major disadvantage is that they did not allow the analysis of blood supply and innervation participation. On the contrary, in vivo models have allowed researchers to identify key immune, vascular and nervous actors of pulpitis and to understand their function and interplay in the inflamed pulp. However, inflammation was mainly induced by iatrogenic dentine drilling associated with simple pulp exposure to the oral environment or stimulation by individual bacterial by-products for short periods. Clearly, these models did not reflect the long and progressive development of dental caries. Lastly, the substantial diversity of the existing models makes experimental data extrapolation to the clinical situation complicated. Therefore, improvement in the design and standardisation of future models, for example by using novel molecular biomarkers, databased models and artificial intelligence, will be an essential step in building an incremental knowledge of pulpitis in the future.

Post-operative discomforts in children after extraction of primary teeth.

OBJECTIVES: This prospective observational study aimed to evaluate discomfort after extraction of deciduous teeth under local anesthesia. The primary objective was to describe the prevalence of post-extraction pain (PEP), post-extraction bleeding (PEB), post-extraction biting injury (PEBI), and analgesic usage in children. The secondary objective was to define whether it is possible to determine a profile of patients or a type of extraction procedure predictive to PEP, administration of analgesics, PEB, or PEBI. METHODS: One hundred and twenty-five children, aged 3-13 years, with indications of at least one deciduous tooth extraction, were included. Immediately after extraction, information concerning the patient and the extraction were collected. Eighteen to 32 hr after extraction, parents were called by phone to request reports concerning the onset and intensity of PEP assessed using the Wong-Baker Faces (WBF) scale, the administration of paracetamol (acetaminophen) to their children, and the appearance of PEB and/or PEBI. RESULTS: Of the children, 37.3% reported PEP (WBF ≥2), but 23.3% of these children did not receive any analgesic drugs to help relieve pain. Pain appeared before 3 hr after extraction in 69% of the children. Higher incidences of PEP and usage of analgesics were found both in the group of children with unfavorable socioeconomic level compared to favorable level and in the group with pre-operative pain compared to no pre-operative pain (p < .05). CONCLUSIONS: About a third of the children reported pain after extraction, but the instructions for pain relief were not followed by all parents. The socioeconomic level of the young patient and the pain felt during the extraction were important predictors of discomfort. Therefore, our study could help the dentist to provide information on predicted post-operative discomfort and to allow suitable care depending on the patient's profile or procedure.

Human Tolerogenic Dendritic Cells Regulate Immune Responses through Lactate Synthesis.

Cell therapy is a promising strategy for treating patients suffering from autoimmune or inflammatory diseases or receiving a transplant. Based on our preclinical studies, we have generated human autologous tolerogenic dendritic cells (ATDCs), which are being tested in a first-in-man clinical trial in kidney transplant recipients. Here, we report that ATDCs represent a unique subset of monocyte-derived cells based on phenotypic, transcriptomic, and metabolic analyses. ATDCs are characterized by their suppression of T cell proliferation and their expansion of Tregs through secreted factors. ATDCs produce high levels of lactate that shape T cell responses toward tolerance. Indeed, T cells take up ATDC-secreted lactate, leading to a decrease of their glycolysis. In vivo, ATDCs promote elevated levels of circulating lactate and delay graft-versus-host disease by reducing T cell proliferative capacity. The suppression of T cell immunity through lactate production by ATDCs is a novel mechanism that distinguishes ATDCs from other cell-based immunotherapies.

Design and characterization of a chitosan-enriched fibrin hydrogel for human dental pulp regeneration.

OBJECTIVE: Regenerating a functional dental pulp in the pulpectomized root canal has been recently proposed as a novel therapeutic strategy in dentistry. To reach this goal, designing an appropriate scaffold able to prevent the growth of residual endodontic bacteria, while supporting dental pulp tissue neoformation, is needed. Our aim was to create an innovative cellularized fibrin hydrogel supplemented with chitosan to confer this hydrogel antibacterial property. METHODS: Several fibrin-chitosan formulations were first screened by rheological analyses, and the most appropriate for clinical use was then studied in terms of microstructure (by scanning electron microscopy), antimicrobial effect (analysis of Enterococcus fæcalis growth), dental pulp-mesenchymal stem/stromal cell (DP-MSC) viability and spreading after 7 days of culture (LiveDead® test), DP-MSC ultrastructure and extracellular matrix deposition (transmission electron microscopy), and DP-MSC proliferation and collagen production (RT-qPCR and immunohistochemistry). RESULTS: A formulation associating 10mg/mL fibrinogen and 0.5% (w/w), 40% degree of acetylation, medium molar mass chitosan was found to be relevant in order to forming a fibrin-chitosan hydrogel at cytocompatible pH (# 7.2). Comparative analysis of fibrin-alone and fibrin-chitosan hydrogels revealed a potent antibacterial effect of the chitosan in the fibrin network, and similar DP-MSC viability, fibroblast-like morphology, proliferation rate and type I/III collagen production capacity. SIGNIFICANCE: These results indicate that incorporating chitosan within a fibrin hydrogel would be beneficial to promote human DP tissue neoformation thanks to chitosan antibacterial effect and the absence of significant detrimental effect of chitosan on dental pulp cell morphology, viability, proliferation and collagenous matrix production.

Current challenges in human tooth revitalization.

Tooth vitality and health are related to the presence of a living connective tissue, the dental pulp (DP), in the center of the dental organ. The DP contains the tooth immune defence system that is activated against invading oral cariogenic bacteria during the caries process and the tissue repair/regeneration machinery involved following microorganisms' eradication. However, penetration of oral bacteria into the DP often leads to complete tissue destruction and colonization of the endodontic space by microorganisms. Classical endodontic therapies consist of disinfecting then sealing the endodontic space with a gutta percha-based material. However, re-infections of the endodontic space by oral bacteria can occur, owing to the lack of tightness of the material. Recent findings suggest that regenerating a fully functional pulp tissue may be an ideal therapeutic solution to maintain a tooth defence system that will detect and help manage future injuries. The objective of this paper was to explain the different revascularization and regeneration strategies that have been proposed to reconstitute a living DP tissue and to discuss the main challenges that have to be resolved to improve these therapeutic strategies.

Tolerogenic dendritic cell therapy in organ transplantation.

Although the occurrence of acute rejection was significantly reduced and the allograft survival at 1 year was massively improved by the development of pharmacological immunosuppressive drugs, little progress has been made regarding long-term graft survival. Cell therapy appears to be an innovative and promising strategy to minimize the use of immunosuppression in transplantation and consequently increases long-term graft survival. The strength of cell therapy is that it will induce graft-specific tolerance and not a general immunosuppression of the patients. Several candidates, such as tolerogenic dendritic cells, have been gaining interest as an efficient means of promoting antigen-specific tolerance over recent years. Studies performed in rodent models have demonstrated the feasibility and efficacy of tolerogenic dendritic cells for the induction of tolerance in transplantation. In parallel, protocols to generate human tolerogenic dendritic cells in vitro have been defined, and some phase I clinical trials in autoimmune diseases have been recently performed to evaluate the safety of tolerogenic dendritic cell therapy. In this review, we will focus on the potential therapeutic interest of these cells in transplantation as well as their generation and characterization in humans. Finally, we will describe our current clinical trial using autologous tolerogenic dendritic cells in transplantation.

Immunophenotyping Reveals the Diversity of Human Dental Pulp Mesenchymal Stromal Cells In vivo and Their Evolution upon In vitro Amplification.

Mesenchymal stromal/stem cells (MSCs) from human dental pulp (DP) can be expanded in vitro for cell-based and regenerative dentistry therapeutic purposes. However, their heterogeneity may be a hurdle to the achievement of reproducible and predictable therapeutic outcomes. To get a better knowledge about this heterogeneity, we designed a flow cytometric strategy to analyze the phenotype of DP cells in vivo and upon in vitro expansion with stem cell markers. We focused on the CD31- cell population to exclude endothelial and leukocytic cells. Results showed that the in vivo CD31- DP cell population contained 1.4% of CD56+, 1.5% of CD146+, 2.4% of CD271+ and 6.3% of MSCA-1+ cells but very few Stro-1+ cells (≤ 1%). CD56+, CD146+, CD271+, and MSCA-1+ cell subpopulations expressed various levels of these markers. CD146+MSCA-1+, CD271+MSCA-1+, and CD146+CD271+ cells were the most abundant DP-MSC populations. Analysis of DP-MSCs expanded in vitro with a medicinal manufacturing approach showed that CD146 was expressed by about 50% of CD56+, CD271+, MSCA-1+, and Stro-1+ cells, and MSCA-1 by 15-30% of CD56+, CD146+, CD271+, and Stro-1+ cells. These ratios remained stable with passages. CD271 and Stro-1 were expressed by <1% of the expanded cell populations. Interestingly, the percentage of CD56+ cells strongly increased from P1 (25%) to P4 (80%) both in all sub-populations studied. CD146+CD56+, MSCA-1+CD56+, and CD146+MSCA-1+ cells were the most abundant DP-MSCs at the end of P4. These results established that DP-MSCs constitute a heterogeneous mixture of cells in pulp tissue in vivo and in culture, and that their phenotype is modified upon in vitro expansion. Further studies are needed to determine whether co-expression of specific MSC markers confers DP cells specific properties that could be used for the regeneration of human tissues, including the dental pulp, with standardized cell-based medicinal products.

Factor analysis of a motivation questionnaire adapted to predoctoral French dental students.

BACKGROUND/PURPOSE: The motivations of dental students for their studies have largely been investigated in numerous countries using psychometric questionnaires. This is not the case in France since validated tools are still lacking. The aim of the present work was dedicated to the psychometric validation of a motivation questionnaire adapted for predoctoral French dental students. MATERIAL AND METHODS: The design corresponded to a monocentric study realized at the dental school of Nantes University, France. A 14-item questionnaire was translated into French and adapted for dental studies. It was autoadministered by the students between March 2014 and May 2014. Exploratory and confirmatory factorial analyses were used to investigate the psychometric properties of the French version. RESULTS: The rate of reply was 88.7% with a sex allocation consisting of 44.4% men and 55.6% women. The internal reliability and the item-sampling adequacy of the questionnaire reached acceptance thresholds. Exploratory and confirmatory factorial analyses established a four-factor structure with good internal reliability. The factors consisted in "altruism," "status and incomes," "scientific curiosity," and "educational advantages." Factors correlated well with the overall questionnaire. The overall motivation score did not differ between male and female students, although "altruism" was best scored by female students while "status and incomes" obtained a higher score in the population of male students. Both male and female students displayed similar "scientific curiosity" and "educational advantages" scorings. CONCLUSION: Our data establish that the French motivation questionnaire has good psychometric properties and that it is relevant for further studies.

Dental Pulp Defence and Repair Mechanisms in Dental Caries.

Dental caries is a chronic infectious disease resulting from the penetration of oral bacteria into the enamel and dentin. Microorganisms subsequently trigger inflammatory responses in the dental pulp. These events can lead to pulp healing if the infection is not too severe following the removal of diseased enamel and dentin tissues and clinical restoration of the tooth. However, chronic inflammation often persists in the pulp despite treatment, inducing permanent loss of normal tissue and reducing innate repair capacities. For complete tooth healing the formation of a reactionary/reparative dentin barrier to distance and protect the pulp from infectious agents and restorative materials is required. Clinical and in vitro experimental data clearly indicate that dentin barrier formation only occurs when pulp inflammation and infection are minimised, thus enabling reestablishment of tissue homeostasis and health. Therefore, promoting the resolution of pulp inflammation may provide a valuable therapeutic opportunity to ensure the sustainability of dental treatments. This paper focusses on key cellular and molecular mechanisms involved in pulp responses to bacteria and in the pulpal transition between caries-induced inflammation and dentinogenic-based repair. We report, using selected examples, different strategies potentially used by odontoblasts and specialized immune cells to combat dentin-invading bacteria in vivo.

Manufacturing of dental pulp cell-based products from human third molars: current strategies and future investigations.

In recent years, mesenchymal cell-based products have been developed to improve surgical therapies aimed at repairing human tissues. In this context, the tooth has recently emerged as a valuable source of stem/progenitor cells for regenerating orofacial tissues, with easy access to pulp tissue and high differentiation potential of dental pulp mesenchymal cells. International guidelines now recommend the use of standardized procedures for cell isolation, storage and expansion in culture to ensure optimal reproducibility, efficacy and safety when cells are used for clinical application. However, most dental pulp cell-based medicinal products manufacturing procedures may not be fully satisfactory since they could alter the cells biological properties and the quality of derived products. Cell isolation, enrichment and cryopreservation procedures combined to long-term expansion in culture media containing xeno- and allogeneic components are known to affect cell phenotype, viability, proliferation and differentiation capacities. This article focuses on current manufacturing strategies of dental pulp cell-based medicinal products and proposes a new protocol to improve efficiency, reproducibility and safety of these strategies.

Human odontoblast-like cells produce nitric oxide with antibacterial activity upon TLR2 activation.

The penetration of cariogenic oral bacteria into enamel and dentin during the caries process triggers an immune/inflammatory response in the underlying pulp tissue, the reduction of which is considered a prerequisite to dentinogenesis-based pulp regeneration. If the role of odontoblasts in dentin formation is well known, their involvement in the antibacterial response of the dental pulp to cariogenic microorganisms has yet to be elucidated. Our aim here was to determine if odontoblasts produce nitric oxide (NO) with antibacterial activity upon activation of Toll-like receptor-2 (TLR2), a cell membrane receptor involved in the recognition of cariogenic Gram-positive bacteria. Human odontoblast-like cells differentiated from dental pulp explants were stimulated with the TLR2 synthetic agonist Pam2CSK4. We found that NOS1, NOS2, and NOS3 gene expression was increased in Pam2CSK4-stimulated odontoblast-like cells compared to unstimulated ones. NOS2 was the most up-regulated gene. NOS1 and NOS3 proteins were not detected in Pam2CSK4-stimulated or control cultures. NOS2 protein synthesis, NOS activity and NO extracellular release were all augmented in stimulated samples. Pam2CSK4-stimulated cell supernatants reduced Streptococcus mutans growth, an effect counteracted by the NOS inhibitor L-NAME. In vivo, the NOS2 gene was up-regulated in the inflamed pulp of carious teeth compared with healthy ones. NOS2 protein was immunolocalized in odontoblasts situated beneath the caries lesion but not in pulp cells from healthy teeth. These results suggest that odontoblasts may participate to the antimicrobial pulp response to dentin-invading Gram-positive bacteria through NOS2-mediated NO production. They might in this manner pave the way for accurate dental pulp healing and regeneration.

Phenotypic analysis of immunocompetent cells in healthy human dental pulp.

INTRODUCTION: Like other tissues in the body, the human dental pulp is equipped with a network of immune cells that can be mobilized against pathogens when they invade the tooth. Very little data, mostly obtained with classic histologic methods, have reported their quantities and relative percentages. The objective of this study was to characterize and precisely quantify immunocompetent cells in healthy human dental pulp by using fluorescence-activated cell sorting, together with identifying specific cell subsets in the leukocyte (CD45(+)) cells. METHODS: Healthy human third molars were collected from 42 young patients. Dental pulps were separated from the hard tissues and prepared for flow cytometry or immunostaining analyses. RESULTS: CD45(+) cells represented 0.94% ± 0.65% of cells obtained from the enzymatic digestion of whole dental pulps (n = 34). CD16(+)CD14(+) granulocytes/neutrophils (50.01% ± 9.08%, n = 7) were found to represent the major subpopulation in CD45(+) cells followed by CD3(+) T lymphocytes (32.58% ± 11%, n = 17), CD14(+) monocytes (8.93% ± 5.8%, n = 7), and HLA-DR(high) Lin1(-) dendritic cells (4.51% ± 1.12%, n = 7). Minor subpopulations included CD3(-)CD56(+) natural killer cells (2.63% ± 1.15%, n = 7) and CD19(+) B lymphocytes (1.65% ± 0.89%, n = 17). We further identified cells harboring a phenotype compatible with Foxp3/CD25-expressing regulatory T lymphocytes (CD45(+)CD3(+)CD4(+)CD127(low)). Fluorescence-activated cell sorting analysis and confocal microscopy also revealed expression of HO-1 in HLA-DR(+) cells. CONCLUSIONS: For the first time, this study identifies and precisely quantifies the relative proportion of immunocompetent cells potentially involved in tissue homeostasis of healthy human dental pulp.

[Extra-oral signs to look for in patients exhibiting oral warning signs of genetic diseases]. / Signes extra-oraux à rechercher face à des signes bucco-dentaires d'alerte de maladies d'origine génétique.

This article is aimed at defining guidelines for dental surgeons to manage patients with warning signs of rare genetic diseases. Anomalies of tooth development may occur as an isolated condition or in association with other symptoms in syndromes. In many cases, dental anomalies may be the first manifestations of a genetic disease. The dentist can contribute to the diagnosis, and hence to an early treatment of this syndrome. When one or more dental anomalies are found, practitioners should refer patients to a genetic clinic or a specialized reference center to diagnose genetic diseases. Therefore, we provide, for the first time, a table of extra-oral signs that dental surgeons can look for in patients exhibiting heritable dental developmental anomalies.

Human dental pulp stem cells cultured in serum-free supplemented medium.

UNLABELLED: Growing evidence show that human dental pulp stem cells (DPSCs) could provide a source of adult stem cells for the treatment of neurodegenerative pathologies. In this study, DPSCs were expanded and cultured with a protocol generally used for the culture of neural stem/progenitor cells. METHODOLOGY: DPSC cultures were established from third molars. The pulp tissue was enzymatically digested and cultured in serum-supplemented basal medium for 12 h. Adherent (ADH) and non-adherent (non-ADH) cell populations were separated according to their differential adhesion to plastic and then cultured in serum-free defined N2 medium with epidermal growth factor (EGF) and basic fibroblast growth factor (bFGF). Both ADH and non-ADH populations were analyzed by FACS and/or PCR. RESULTS: FACS analysis of ADH-DPSCs revealed the expression of the mesenchymal cell marker CD90, the neuronal marker CD56, the transferrin receptor CD71, and the chemokine receptor CXCR3, whereas hematopoietic stem cells markers CD45, CD133, and CD34 were not expressed. ADH-DPSCs expressed transcripts coding for the Nestin gene, whereas expression levels of genes coding for the neuronal markers ß-III tubulin and NF-M, and the oligodendrocyte marker PLP-1 were donor dependent. ADH-DPSCs did not express the transcripts for GFAP, an astrocyte marker. Cells of the non-ADH population that grew as spheroids expressed Nestin, ß-III tubulin, NF-M and PLP-1 transcripts. DPSCs that migrated out of the spheroids exhibited an odontoblast-like morphology and expressed a higher level of DSPP and osteocalcin transcripts than ADH-DPSCs. CONCLUSION: Collectively, these data indicate that human DPSCs can be expanded and cultured in serum-free supplemented medium with EGF and bFGF. ADH-DPSCs and non-ADH populations contained neuronal and/or oligodendrocyte progenitors at different stages of commitment and, interestingly, cells from spheroid structures seem to be more engaged into the odontoblastic lineage than the ADH-DPSCs.

Lipopolysaccharide-binding protein inhibits toll-like receptor 2 activation by lipoteichoic acid in human odontoblast-like cells.

INTRODUCTION: Previous studies have suggested that odontoblasts sense gram-positive bacteria components through Toll-like receptor 2 (TLR2) and trigger dental pulp immunity by producing proinflammatory cytokines. Currently, the factors that modulate odontoblast TLR2 activation are unknown. Our aim was to investigate lipopolysaccharide-binding protein (LBP) effects on the TLR2-mediated odontoblast response. METHODS: Human odontoblast-like cells were stimulated with lipoteichoic acid (LTA) (a TLR2 ligand), LBP, CD14 (a TLR2 cofactor), or various combinations of LTA/LBP, LTA/CD14, or LTA/CD14/LBP. CXCL8, IL6, and TLR2 gene expression was assessed by real-time polymerase chain reaction. CXCL8 and interleukin (IL)-6 production was determined by enzyme-linked immunosorbent assay in culture supernatants of cells stimulated with LTA, LTA/CD14, or LTA/CD14/LBP. LBP effects on nuclear factor kappa B (NF-κB), p38, JNK, ERK, STAT3, and p70S6 signaling pathways were determined in LTA-stimulated odontoblast-like cells with a multiplex biometric immunoassay. LBP effects were compared with specific inhibitors of these signaling pathways. LBP transcript and protein were investigated in vivo in healthy and inflamed dental pulps by real-time polymerase chain reaction and immunohistochemistry. RESULTS: Activation of CXCL8, IL6, and TLR2 gene expression and CXCL8 and IL-6 secretion in LTA- and LTA/CD14-stimulated odontoblast-like cells was significantly decreased by LBP. LBP inhibited NF-κB and p38 signaling pathways in LTA-stimulated cells in a similar way to NF-κB and p38 inhibitors. LBP transcript and protein were detected in vivo in inflamed dental pulps but not in healthy ones. CONCLUSIONS: These results demonstrate that LBP reduces TLR2-dependent production of inflammatory cytokines by odontoblast-like cells. We suggest that in this way it could modulate host defense in human dental pulp.

Evaluation of the ability of laser Doppler flowmetry for the assessment of pulp vitality in general dental practice.

OBJECTIVES: In this study we investigated pulpal blood flow (PBF) values and moving blood cell velocity (MBCV) curves recorded by laser Doppler flowmetry (LDF) for pulpal vitality diagnosis in general dental practice and to compare MBCV curves to standard diagnostic tests in traumatology. STUDY DESIGN: LDF tests performed with the PeriFlux System 5000 were applied to vital and nonvital (endodontic treatment) teeth of healthy students (n = 52) and on 24 luxated teeth of patients. RESULTS: The PBF values were not reproducible and no statistically significant differences were observed between vital and nonvital teeth. MBCV curves in contrast could distinguish between the 2 tooth types. Tests on luxated teeth showed that while 62.5% of MBCV curves correlated with conventional vitality tests, only 12.5% of MBCV curves could help in vital diagnosis. CONCLUSION: When applied to luxated teeth, the MBCV curve appeared to be accurate when the standard vitality tests indicated a nonvital diagnosis.

Superiority of bone marrow-derived dendritic cells over monocyte-derived ones for the expansion of regulatory T cells in the macaque.

Regulatory T cells (Treg) have been identified as playing a pivotal role in the control of tolerance and in the suppression of pathologic immune responses in autoimmune diseases, transplantation, and graft-versus-host disease. Treg expanded ex vivo by dendritic cells could be potential reagents to promote antigen-specific tolerance in vivo. However, in vivo studies have been carried out mostly in rodents and will need validation in primates before clinical application. We characterized macaque dendritic cell derived either from bone marrow with and without prior CD34+ cell selection (BMDC), or from CD14+ peripheral blood mononuclear cells (Mo-DC). We demonstrate that with a semi-mature phenotype, BMDC are superior to Mo-DC in their capacity to expand freshly isolated allogeneic macaque CD4+ CD25+ CD127- Foxp3+ Treg in vitro in the presence of interleukin-2. Moreover, the expanded Treg maintain their phenotype and suppressive activity. These data provide a step toward the use of macaque dendritic cell to expand Treg for future preclinical testing.

[Stem cells of dental pulp]. / Les cellules souches de la pulpe dentaire.

Any clinician dreams to obtain the regeneration of the destroyed organ for his patient. In the human being, the regeneration of complex structures is not possible, except the liver and the bone marrow, which can be regenerated because of the presence of adult stem cells in these tissues. The stem cells have two principal properties: they ensure their self-renewal and they have the ability to differentiate into several cellular types. Using specific markers allowing the identification of the stem cells in bone marrow, stem cells were observed in dental pulp tissues. Although the origin, the identification, and the localization of these stem cells of dental pulp remain under consideration, the optimism in research on stem cells permits to believe that the knowledge on dental stem cells will lead to their use in therapeutics.