"Dental Pulp-On-Chip" Microfluidic Devices for Emulating Human Dental Pulp Tissue Physiology and Pathology.

Regeneration of dental pulp after pulpectomy was accomplished recently by autologous transplantation of dental pulp stem/ progenitor cells into the root canal. The identical patterns of qualitative and quantitative protein and mRNA expression in the regenerated pulp and normal pulp demonstrated complete pulp regeneration. The lack of tissue specific markers in the dental pulp is a major challenge in dental regenerative medicine. In order to identify specific markers in dental pulp we undertook a comparison of the gene expression profile of the dental pulp with that of periodontal ligament and gingiva. This systematic investigation identified thyrotropinreleasing hormone (TRH)-degrading enzyme (DE) as a marker of dental pulp. Expression of TRH-DE mRNA in human dental pulp was higher than that in any other tissue except brain as analyzed by real time RT-PCR. Induction of neural cells enhanced the expression of TRH-DE mRNA in dental pulp stem/progenitor cells (CD105+ and CD31- side population (SP) cells) in vitro. Immunohistochemical and in situ hybridization analyses demonstrated that TRH-DE in the neuronal processes in dental pulp. In canine pulp cells, TRH down-regulated TRH-DE mRNA expression, while neuropeptide Y up-regulated it, suggesting that TRH-DE has functional role in the neuropeptide signaling in dental pulp tissue. It is noteworthy that TRH-DE mRNA was expressed in the regenerated pulp 28 days after transplantation of CD31- SP cells into root canals after pulpectomy. These results demonstrate the utility of TRH-DE as a novel dental pulp biomarker during regeneration of pulp.

Magnetic resonance imaging in endodontics: a literature review

Leptin Promotes Dentin Sialophosphoprotein Expression in Human Dental Pulp

Dental pulp as a source of nutrition for the whole tooth is vulnerable to trauma and bacterial invasion, which causes irreversible pulpitis and pulp necrosis. Dental pulp regeneration is a valuable method of restoring the viability of the dental pulp and even the whole tooth. Odontogenic mesenchymal stem cells (MSCs) residing in the dental pulp environment have been widely used in dental pulp regeneration because of their immense potential to regenerate pulp-like tissue. Furthermore, the regenerative abilities of odontogenic MSCs are easily affected by the microenvironment in which they reside. The natural environment of the dental pulp has been proven to be capable of regulating odontogenic MSC homeostasis, proliferation, and differentiation. Therefore, various approaches have been applied to mimic the natural dental pulp environment to optimize the efficacy of pulp regeneration. In addition, odontogenic MSC aggregates/spheroids similar to the natural dental pulp environment have been shown to regenerate well-organized dental pulp both in preclinical and clinical trials. In this review, we summarize recent progress in odontogenic MSC-mediated pulp regeneration and focus on the effect of the microenvironment surrounding odontogenic MSCs in the achievement of dental pulp regeneration.

Role of Angiogenesis in Endodontics: Contributions of Stem Cells and Proangiogenic and Antiangiogenic Factors to Dental Pulp Regeneration

A Decellularized Matrix Hydrogel Derived from Human Dental Pulp Promotes Dental Pulp Stem Cell Proliferation, Migration, and Induced Multidirectional Differentiation In Vitro

Vascular and lymphatic heterogeneity and age-related variations of dental pulps

Roles of basic fibroblast growth factor, stem cells from dental pulp and apical papilla in the repair and regeneration of dental pulp and other tissues/organs

The dental pulp is a highly vascularized and innervated connective tissue composed of various cell types, including fibroblasts, odontoblasts, mesenchymal stem cells, neuronal, and endothelial cells. The interplay between these diverse cell populations is pivotal for dental pulp tissue homeostasis and regeneration after carious infections and traumatic tooth lesions. Despite the great clinical need, comprehensive in vitro models that accurately recapitulate the complexity of the dental pulp are still missing, hampering the development of novel, faster, and more effective therapies. In this study, an innovative “tooth‐on‐chip” microfluidic device is presented to emulate the composition and three‐dimensional structure of the dental pulp tissue in vitro. Co‐culture of human dental pulp stem cells, odontoblast‐like cells, endothelial cells, and trigeminal neurones in this miniaturized system successfully reproduced the structural organization and physiology of the dental pulp. The microfluidic device integrated various compartments that allowed the generation of complex vascular and neuronal networks, the formation of stem cell perivascular niches, and the formation of an odontoblast/dentine interface. The “tooth‐on‐chip” device represents a conceptual leap in replicating dental pulp physiology in vitro, offering a state‐of‐the‐art platform to study dental pulp physiology and pathology and serving as a benchmark to create more advanced tooth simulation systems.

Dental pulp regeneration is significantly aided by human dental pulp stem cells (hDPSCs). An increasing number of studies have demonstrated that circular RNAs (circRNAs) are crucial in the multidirectional differentiation of many mesenchymal stem cells, but their specific functions and mechanisms remain unknown. This work aimed at elucidating the molecular mechanism by which hsa_circ_0001599 works in hDPSCs during odontogenic differentiation. The expression of hsa_circ_0001599 in hDPSCs and dental pulp tissue was determined by using quantitative real-time PCR (qRT‒PCR). The role of hsa_circ_0001599 in the odontogenic differentiation of hDPSCs and its mechanism were studied using a variety of in vivo and in vitro assessments. The odontogenic differentiation of hDPSCs was facilitated by the overexpression of hsa_circ_0001599, which activated the PI3K/AKT signalling pathway in vitro. In vivo, hsa_circ_0001599 can promote the formation of new dentin-like structures. Mechanistically, hsa_circ_0001599 enhanced ITGA2 expression by sponging miR-889-3p. Furthermore, hsa_circ_0001599 interacts with the methylation reader hnRNPA2B1, promoting hnRNPA2B1 translocation from the nucleus to the cytoplasm and increasing ITGA2 mRNA stability. This research revealed the important role of hsa_circ_0001599 in odontogenic differentiation. Thus, hDPSCs engineered with hsa_circ_0001599 have the potential to be effective therapeutic targets for dental pulp repair and regeneration.

Schwann cell-derived EVs facilitate dental pulp regeneration through endogenous stem cell recruitment via SDF-1/CXCR4 axis

Adipose Tissue–derived Microvascular Fragments as Vascularization Units for Dental Pulp Regeneration

Dental pulp homeostasis and regeneration critically depend on angiogenesis, the formation of new capillaries from preexisting blood vessels. Regenerative endodontics has emerged as a clinical strategy to restore damaged or diseased dental pulp tissues using stem cells, signalling molecules, and scaffolds. Enhanced cell viability and angiogenesis are essential for the success of such regenerative therapies. However, their development, as well as efficient drug and biomaterial testing, is limited by the lack of physiologically relevant models. In this study, we developed a microfluidic model of angiogenesis in the human dental pulp to investigate the effects of drugs and biomaterials commonly used in dentistry. We optimised culture conditions influencing angiogenic sprouting and found that the presence of dental pulp cells and lower fibrin concentrations promoted angiogenesis significantly. Furthermore, static culture conditions enhanced sprouting compared with co- or contra-directional hydrostatic pressure-driven flow. Using this platform, we tested drugs (Paclitaxel and Limantrafin) and biomaterials (HEMA and Emdogain®). The model enabled quantitative imaging of angiogenic sprout growth and assessment of cytotoxicity through analysis of the culture medium. Importantly, the timing of drug exposure proved critical: early treatment inhibited sprout formation, whereas later treatment compromised the stability and viability of established vessels. HEMA (10 mM) resulted in cytotoxicity and compromised vessels, whereas Emdogain (1 mg/ml) showed no cytotoxicity and no significant impact on vessel formation. Paclitaxel efficiently inhibited angiogenesis at low concentrations (50 nM) with low cell death while Limantrafin required high concentrations (1 mM) to inhibit angiogenesis while showing elevated cell death and cytotoxicity. In conclusion, this microfluidic model provides a robust tool for studying fundamental angiogenic processes in the human dental pulp and offers an improved platform for safe and effective drug and biomaterial testing, thereby advancing regenerative endodontic therapies.

Application of neurotransmitters and dental stem cells for pulp regeneration: A review

BackgroundSignal peptide-CUB-EGF domain-containing protein 3 (SCUBE3), a secreted multifunctional glycoprotein whose transcript expression is restricted to the tooth germ epithelium during the development of embryonic mouse teeth, has been demonstrated to play a crucial role in the regulation of tooth development. Based on this, we hypothesized that epithelium-derived SCUBE3 contributes to bio-function in dental mesenchymal cells (Mes) via epithelium–mesenchyme interactions.MethodsImmunohistochemical staining and a co-culture system were used to reveal the temporospatial expression of the SCUBE3 protein during mouse tooth germ development. In addition, human dental pulp stem cells (hDPSCs) were used as a Mes model to study the proliferation, migration, odontoblastic differentiation capacity, and mechanism of rhSCUBE3. Novel pulp–dentin-like organoid models were constructed to further confirm the odontoblast induction function of SCUBE3. Finally, semi-orthotopic animal experiments were performed to explore the clinical application of rhSCUBE3. Data were analysed using one-way analysis of variance and t-tests.ResultsThe epithelium-derived SCUBE3 translocated to the mesenchyme via a paracrine pathway during mouse embryonic development, and the differentiating odontoblasts in postnatal tooth germ subsequently secreted the SCUBE3 protein via an autocrine mechanism. In hDPSCs, exogenous SCUBE3 promoted cell proliferation and migration via TGF-β signalling and accelerated odontoblastic differentiation via BMP2 signalling. In the semi-orthotopic animal experiments, we found that SCUBE3 pre-treatment-induced polarized odontoblast-like cells attached to the dental walls and had better angiogenesis performance.ConclusionSCUBE3 protein expression is transferred from the epithelium to mesenchyme during embryonic development. The function of epithelium-derived SCUBE3 in Mes, including proliferation, migration, and polarized odontoblastic differentiation, and their mechanisms are elaborated for the first time. These findings shed light on exogenous SCUBE3 application in clinic dental pulp regeneration.