Effects of human vascular endothelial growth factor on reparative dentin formation

The lipoteichoic acid of Lactobacillus plantarum effect on lymphocyte, VEGF-A and TGF-β expression in male rat dental pulp

OBJECTIVE

Lipoteichoic acid from Lactobacillus plantarum (L. plantarum) is a significant virulence factor that exacerbates pulp inflammation. Lipoteichoic acid plays a role in modulating the inflammatory to proliferative phase transition is crucial in determining the outcome of pulp healing or necrosis. This study explores the role of L. plantarum on lymphocytes and the expression of transforming growth factor β1 (TGF-β1) and vascular endothelial growth factor A (VEGF-A) in a male rat model of acute dental pulp injury.

DESIGN

The acute dental pulp model was created in the upper molar of Rattus novergicus using a round bur. Then, the dental pulp was exposed to 10 µg/ml of the lipoteichoic acid of L. plantarum and filled with a temporary filling. In the next 24, 48, and 72 h, each animal was decapitated, and the expression of TGF-β1 and VEGF-A in dental pulp was analyzed using indirect immunohistochemistry, while the lymphocytes analyzed using hematoxyline-eosin staining.

RESULT

Lipoteichoic acid of L. plantarum induced acute dental pulp by increasing the lymphocyte number after 48 and 72 h of exposure (p < 0.05). While, inhibiting TGF-β1 expression after 48 and 72 h of exposure (p < 0.05), and VEGF-A was inhibiting after 72 h of exposure (p < 0.05).

CONCLUSION

Exposure to lipoteichoic acid from L. plantarum significantly accelerates the inflammatory response in the dental pulp. However, this accelerated inflammation disrupts the proliferative phase, potentially leading to more extensive damage to the dental pulp.

Gut microbiome as biomarker for triclosan toxicity in Labeo rohita: bioconcentration, immunotoxicity and metagenomic profiling

Triclosan (TCS) is a lipophilic, broad spectrum antimicrobial agent commonly used in personal care products with a projected continuous escalation in aquatic environments in the post COVID 19 era. There is rich documentation in the literature on the alteration of physiological responses in fish due to TCS exposure; however, studies on gut associated bacteria of fish are still scarce. This is the first attempt to determine changes in bacterial community structure due to exposure of TCS on Labeo rohita, a commercially essential freshwater species, using 16S V3-V4 region ribosomal RNA (rRNA) next-generation sequencing (NGS). Chronic exposure of TCS at environmentally realistic concentrations viz. 1/5th (T1: 0.129 mg/L) and 1/10th (T2: 0.065 mg/L) of LC50 for 28 days resulted in the dose dependent bioconcentration of TCS in the fish gut. Prolonged exposure to TCS leads to disruption of gut bacteria evidenced by down regulation of the host immune system. Additionally, high-throughput sequencing analysis showed alternation in the abundance and diversity of microbial communities in the gut, signifying Proteobacteria and Verrucomicrobia as dominant phyla. Significant changes were also observed in the relative abundance of Chloroflexi and Gammatimonadetes phyla in TCS exposed groups. The study revealed that gut microbiome can be used as a biomarker in assessing the degree of TCS toxicity in commercially important fish species.

Tissue engineering approaches for dental pulp regeneration: The development of novel bioactive materials using pharmacological epigenetic inhibitors

The drive for minimally invasive endodontic treatment strategies has shifted focus from technically complex and destructive root canal treatments towards more conservative vital pulp treatment. However, novel approaches to maintaining dental pulp vitality after disease or trauma will require the development of innovative, biologically-driven regenerative medicine strategies. For example, cell-homing and cell-based therapies have recently been developed in vitro and trialled in preclinical models to study dental pulp regeneration. These approaches utilise natural and synthetic scaffolds that can deliver a range of bioactive pharmacological epigenetic modulators (HDACis, DNMTis, and ncRNAs), which are cost-effective and easily applied to stimulate pulp tissue regrowth. Unfortunately, many biological factors hinder the clinical development of regenerative therapies, including a lack of blood supply and poor infection control in the necrotic root canal system. Additional challenges include a need for clinically relevant models and manufacturing challenges such as scalability, cost concerns, and regulatory issues. This review will describe the current state of bioactive-biomaterial/scaffold-based engineering strategies to stimulate dentine-pulp regeneration, explicitly focusing on epigenetic modulators and therapeutic pharmacological inhibition. It will highlight the components of dental pulp regenerative approaches, describe their current limitations, and offer suggestions for the effective translation of novel epigenetic-laden bioactive materials for innovative therapeutics.

Regenerative endodontic therapy: From laboratory bench to clinical practice

BACKGROUND

Maintaining the vitality and functionality of dental pulp is paramount for tooth integrity, longevity, and homeostasis. Aiming to treat irreversible pulpitis and necrosis, there has been a paradigm shift from conventional root canal treatment towards regenerative endodontic therapy.

AIM OF REVIEW

This extensive and multipart review presents crucial laboratory and practical issues related to pulp-dentin complex regeneration aimed towards advancing clinical translation of regenerative endodontic therapy and enhancing human life quality.

KEY SCIENTIFIC CONCEPTS OF REVIEW

In this multipart review paper, we first present a panorama of emerging potential tissue engineering strategies for pulp-dentin complex regeneration from cell transplantation and cell homing perspectives, emphasizing the critical regenerative components of stem cells, biomaterials, and conducive microenvironments. Then, this review provides details about current clinically practiced pulp regenerative/reparative approaches, including direct pulp capping and root revascularization, with a specific focus on the remaining hurdles and bright prospects in developing such therapies. Next, special attention was devoted to discussing the innovative biomimetic perspectives opened in establishing functional tissues by employing exosomes and cell aggregates, which will benefit the clinical translation of dental pulp engineering protocols. Finally, we summarize careful consideration that should be given to basic research and clinical applications of regenerative endodontics. In particular, this review article highlights significant challenges associated with residual infection and inflammation and identifies future insightful directions in creating antibacterial and immunomodulatory microenvironments so that clinicians and researchers can comprehensively understand crucial clinical aspects of regenerative endodontic procedures.

Physico-chemical and biological characterization of synthetic and eggshell derived nanohydroxyapatite/carboxymethyl chitosan composites for pulp-dentin tissue engineering

Hybrid nanohydroxyapatite/carboxymethyl chitosan (nHAp-CMC) scaffolds have garnered significant attention in the field of regenerative engineering. The current study comparatively analyzed the physicochemical and biological properties of synthetic nanohydroxyapatite (SnHA)- and eggshell-sourced nanohydroxyapatite (EnHA)- based CMC biocomposites for pulp-dentin regeneration. EnHA and CMC were synthesized through a chemical process, whereas SnHA was commercially obtained. Composite scaffolds of SnHA-CMC and EnHA-CMC (1:5 w/w) were prepared using freeze-drying method. All biomaterials were characterized by FTIR, micro-Raman, XRD, HRSEM-EDX, and TEM analyses, and their in vitro bioactivity was assessed by immersing them in simulated body fluid for 21 days. The biological properties of the composite scaffolds were evaluated by assessing cytocompatibility using MTT assay and biomineralization potential by analyzing the odontogenic gene expressions (ALP, DSPP, DMP-1 and VEGF) in human dental pulp stem cells (DPSCs) using RT-qPCR method. Characterization studies revealed that EnHA displayed higher crystallinity and superior surface morphology compared to SnHA. The composite scaffolds showed a highly interconnected porous microstructure with pore sizes ranging between 60 and 220 μm, ideal for cell seeding. All tested materials, SnHA, EnHA, and their respective composites, displayed high cytocompatibility, increased ALP activity and degree of mineralization with significant upregulation of odontogenic-related genes on DPSCs (p < 0.05). Nevertheless, the odontogenic differentiation potential of EnHA-CMC on DPSCs was significantly higher when compared to SnHA-CMC. The findings from this study highlight the potential of EnHA-CMC as a promising candidate for pulp-dentin engineering.

Evaluation of the genotoxicity, cytotoxicity, and bioactivity of calcium silicate-based cements

BACKGROUND

As calcium silicate-based cements (CSCs) have found success in various vital pulp therapy applications, several new CSC products have emerged. This study aimed to assess the genotoxicity, cytotoxicity, and bioactivity of four CSCs by comparing the newly introduced materials Bio MTA+ and MTA Cem with previously studied materials, Biodentine and NeoMTA.

METHODS

Genotoxicity was evaluated using the micronucleus (MN) assay in human peripheral blood lymphocyte cells, measuring MN frequency and nuclear division index (NDI). Cytotoxicity was assessed in human dental pulp stem cells through the Water-Soluble Tetrazolium Salt-1 (WST-1) colorimetric assay. Bioactivity was determined by ELISA, measuring the levels of angiogenic and odontogenic markers (BMP-2, FGF-2, VEGF, and ALP). Statistical analyses included ANOVA, Dunnet and Sidak tests, and Wald chi-square test. (p < .05).

RESULTS

The MN frequency in the groups was significantly lower than that in the positive control group (tetraconazole) (p < .05). NDI values decreased with increasing concentration (p < .05). Bio MTA+ and NeoMTA showed decreased cell viability at all concentrations in 7-day cultures (p < .01). All materials increased BMP-2, FGF-2, and VEGF levels, with Biodentine and NeoMTA showing the highest levels of BMP-2 and FGF-2 on day 7. Biodentine displayed the highest VEGF levels on day 7. Biodentine and NeoMTA groups exhibited significantly higher ALP activity than the Bio MTA+ and MTA Cem groups by day 7.

CONCLUSION

Bio MTA+ and MTA Cem demonstrated no genotoxic or cytotoxic effects. Moreover, this study revealed bioactive potentials of Bio MTA+ and MTA Cem by enhancing the expression of angiogenic and osteogenic growth factors.

The Role of Growth Factor Delivery Systems on Cellular Activities of Dental Stem Cells: A Systematic Review (Part II)

OBJECTIVE

The current systematic review aims to provide the available ex vivo evidence evaluating the biological interactions of dental stem cells (DSCs) and growth factor delivery systems.

METHODS

Following the Preferred Reporting Items for a Systematic Reviews and Meta-Analyses (PRISMA) guidelines, systematic search was conducted in the electronic databases (PubMed/Medline, Scopus, Web of Science, and Google Scholar) up to January 2022. Studies evaluating the biological interactions of DSCs and growth factor delivery systems were included. The outcome measures were cell cytocompatibility, mineralization, and differentiation.

RESULTS

Sixteen studies were selected for the qualitative synthesis. The following growth factor delivery systems exhibit adequate cytocompatibility, enhanced mineralization, and osteo/odontoblast differentiation potential of DSCs: 1) Fibroblast growth factor (FGF-2)-loaded-microsphere and silk fibroin, 2) Bone morphogenic protein-2 (BMP-2)-loaded-microsphere and mesoporous calcium silicate scaffold, 3) Transforming growth factor Beta 1 (TGF-ß1)-loaded-microsphere, glass ionomer cement (GIC), Bio-GIC and liposome, 4) TGF-ß1-loaded-nanoparticles/scaffold, 5) Vascular endothelial growth factor (VEGF)-loaded-fiber and hydrogel, 6) TGF-ß1/VEGF-loaded-nanocrystalline calcium sulfate/hydroxyapatite/calcium sulfate, 7) Epidermal growth factor-loaded- nanosphere, 8) Stem cell factor/DSCs-loaded-hydrogel and Silk fibroin, 9) VEGF/BMP-2/DSCs-loaded-Three-dimensional matrix, 10) VEGF/DSCs-loaded-microsphere/hydrogel, and 11) BMP-2/DSCs and VEGF/DSCs-loaded-Collagen matrices. The included delivery systems showed viability, except for Bio-GIC on day 3. The choice of specific growth factors and delivery systems (i.e., BMP-2-loaded-microsphere and VEGF-loaded-hydrogel) resulted in a greater gene expression.

CONCLUSIONS

This study, with low-level evidence obtained from ex vivo studies, suggests that growth factor delivery systems induce cell proliferation, mineralization, and differentiation toward a therapeutic potential in regenerative endodontics.

Vascular Endothelial Growth Factor A serum levels and common gene polymorphisms in generalized periodontitis affected patients

OBJECTIVE

To evaluate and compare the associations of VEGFA serum levels and SNPs (rs1570360, rs699947, rs3025033, and rs2146323) with periodontitis in study participants grouped by gender.

METHODS

The study enrolled 261 patients with periodontitis and 441 healthy controls as a reference group. Patients underwent periodontal examination and radiographic analysis to confirm the periodontitis diagnosis. Blood samples were collected, and the DNA salting-out method was used for DNA extraction from peripheral venous blood. Genotyping of VEGFA (rs1570360, rs699947, rs3025033, and rs2146323) was performed using real-time polymerase chain reaction (RT-PCR) and serum level analysis was done for 80 individuals - 40 periodontitis-affected patients and 40 reference group subjects.

RESULTS

The analysis of VEGFA (rs1570360, rs699947, rs3025033, and rs2146323) showed that the rs3025033 GG genotype was less frequent in the periodontitis group than in the reference group (1.6% vs. 5.7%,p = 0.008). VEGFA serum levels were not statistically significantly different between periodontitis patients and reference group subjects (554.29 (522.38) ng/ml vs. 581.32 (348.16) ng/ml, p = 0.786). Individuals carrying rs1570360, rs699947, rs3025033, and rs2146323 haplotype A-A-G-A had decreased risks of periodontitis, while rare haplotype of VEGFA (rs1570360, rs699947, rs3025033, and rs2146323) was associated with increased odds of periodontitis (OR= 0.42; 95% CI: 0.20-0.85; p < 0.017; OR= 4.08; 95% CI: 1.86-8.94; p < 0.0001, respectively).

CONCLUSION

The rs3025033 GG genotype and the rs1570360, rs699947, rs3025033, and rs2146323 A-A-G-A haplotypes may play a protective role in the development of periodontitis, but a less common haplotype of the same VEGFA polymorphism may be associated with the risk of developing periodontitis.

Effects of histone acetyltransferase (HAT) and histone deacetylase (HDAC) inhibitors on proliferative, differentiative, and regenerative functions of Toll-like receptor 2 (TLR-2)-stimulated human dental pulp cells (hDPCs)

OBJECTIVES

This in vitro study aimed to modify TLR-2-mediated effects on the paracrine, proliferative, and differentiation potentials of human dental pulp-derived cells using histone acetyltransferase (HAT) and histone deacetylase (HDAC) inhibitors.

MATERIALS AND METHODS

Cell viability was assessed using the XTT assay. Cells were either treated with 10 μg/ml Pam3CSK4 only, or pre-treated with valproic acid (VPA) (3 mM), trichostatin A (TSA) (3 μM), and MG-149 (3 μM) for a total of 4 h and 24 h. Control groups included unstimulated cells and cells incubated with inhibitors solvents only. Transcript levels for NANOG, OCT3-4, FGF-1 and 2, NGF, VEGF, COL-1A1, TLR-2, hβD-2 and 3, BMP-2, DSPP, and ALP were assessed through qPCR.

RESULTS

After 24 h, TSA pre-treatment significantly upregulated the defensins and maintained the elevated pro-inflammatory cytokines, but significantly reduced healing and differentiation genes. VPA significantly upregulated the pro-inflammatory cytokine levels, while MG-149 significantly downregulated them. Pluripotency genes were not significantly affected by any regimen.

CONCLUSIONS

At the attempted concentrations, TSA upregulated the defensins gene expression levels, and MG-149 exerted a remarkable anti-inflammatory effect; therefore, they could favorably impact the immunological profile of hDPCs.

CLINICAL RELEVANCE

Targeting hDPC nuclear function could be a promising option in the scope of the biological management of inflammatory pulp diseases.

Micro-CT Evaluation of Spontaneous Apexification of an Immature Tooth following Trauma

This case reports on the micro-computerised tomography (CT) images of a periapical calcified dome following spontaneous apexification as a subsequence of trauma. An immature, maxillary central incisor was found to be non-vital one month following trauma. The tooth had minimal signs of structural damage; however, there was radiographic evidence of spontaneous apexification. The tooth suffered a second traumatic episode two years later and was decoronated to facilitate bone retention during osseous development. The patient presented with swelling and pain 36 months later, and the tooth root was extracted. The root was embedded in resin, and cross-sectional images were obtained using micro-CT. Analysis of the images provided insight into the structure of the calcified dome that formed following the first traumatic injury.

Characterization of nano-hydroxyapatite incorporated carboxymethyl chitosan composite on human dental pulp stem cells

AIM

To compare the odontogenic differentiation potential of a composite scaffold (CSHA) comprising of nano-hydroxyapatite (nHAp) and carboxymethyl chitosan (CMC) with Biodentine on human dental pulp stem cells (hDPSCs).

METHODOLOGY

A CSHA scaffold was prepared through an ultrasonication route by adding nHAp and CMC (1:5 w/w) in water medium followed by freeze-drying. Physicochemical characterization was achieved using scanning electron microscopy with energy-dispersive X-ray spectroscopy, X-ray diffraction and Fourier transform infrared spectroscopy. In-vitro bioactivity and pH assessments were done by soaking in simulated body fluid (SBF) for 28 days. The angiogenic and odontogenic differentiation abilities were assessed by expression of vascular endothelial growth factor (VEGF) and Dentine sialophosphoprotein (DSPP) markers on cultured hDPSCs by flow cytometry and RT-qPCR at 7, 14 and 21 days. Cell viability/proliferation and biomineralization abilities of CSHA were compared with Biodentine by MTT assay, alkaline phosphatase (ALP) activity, Alizarin Red Staining (ARS) and osteopontin (OPN) expression on hDPSCs following 7 and 14 days. Data were statistically analysed with Kruskal Wallis and Friedman tests as well as one way anova followed by appropriate post hoc tests (p < .05).

RESULTS

Characterization experiments revealed a porous microstructure of CSHA with pore diameter ranging between 60 and 200 μm and 1.67 Ca/P molar ratio along with the characteristic functional groups of both HAp and CMC. CSHA displayed bioactivity in SBF by forming apatite-like crystals and maintained a consistent pH value of 7.70 during 28 days' in vitro studies. CSHA significantly upregulated VEGF and DSPP levels on hDPSCs on day 21 compared with day 7 (p < .05). Further, CSHA supported cell viability/proliferation over 14 days like Biodentine with no statistical differences (p > .05). However, CSHA exhibited increased ALP and ARS activity with an intense OPN staining compared with Biodentine after 14 days (p < .05).

CONCLUSION

The results highlighted the odontogenic differentiation and biomineralization abilities of CSHA on hDPSCs with significant VEGF and DSPP gene upregulations. Further, CSHA exhibited enhanced mineralization activity than Biodentine, as evidenced by increased ALP, ARS and OPN activity on day 14. The nHAp-CMC scaffold has the potential to act as an effective pulp capping agent; however, this needs to be further validated through in-vivo animal studies.

Effects of hydroxyapatite nanorods prepared through Elaeagnus Angustifolia extract on modulating immunomodulatory/dentin-pulp regeneration genes in DPSCs

Dental pulp stem cells (DPSCs) are a new type of mesenchymal stem cells (MSCs) found in the oral cavity with immunomodulation and tissue regeneration capacities. This study determined the impacts of nano-hydroxyapatite (nHA) prepared through Elaeagnus Angustifolia extract (EAE) to enhance the relative expression of immunomodulatory/dentin-pulp regeneration genes in DPSCs. To produce nHA and modified nHA via EAE (nHAEA), the sol-gel technique was used. The functional groups of nanoparticles (NPs), morphological, and optical features were determined using Fourier transform infrared (FTIR), X-ray diffraction (XRD), Scanning electron microscopy (SEM) together with energy-dispersive X-ray analysis (EDAX), and Transmission electron microscopy (TEM). The cell viability was then determined using the MTT method in the presence of various EAE, nHA, and nHAEA concentrations. Target gene expression was quantified using a real-time PCR procedure after treating DPSCs with an optimally non-toxic dose of EAE and NPs. The presence of the HA phase was reported with the XRD and FTIR results. According to the results of SEM and TEM, the rod-like NPs could be fabricated. nHAEAs were found to be characterized with low crystallite size, reduced diameter, lengthier, needle-like, and less agglomerated particles compared with nHA. The real-time PCR results demonstrated that nHAEA remarkably increased the expression of human leukocyte antigen-G5 (HLA-G5), vascular endothelial growth factor (VEGF), dentin sialophosphoprotein (DSPP), and interleukin6 (IL6) genes compared to the nHA group. These findings suggest that nHAEAs might have the potential application in the stemness capability of DPSCs for the treatment of inflamed/damaged pulp.

CaCO3 from Anadara granosa shell as reparative dentin inducer in odontoblast pulp cells: In-vivo study

Introduction

Anadara granosa (blood clam) shell contained 98.7% of calcium carbonate (CaCO3). This material has bio-properties that able to induced the dentin regeneration. This study is expected to reveal the nuclear factor kappa beta (NF-kB), transforming growth factor beta (TGF-β1), and vascular endothelial growth factor A (VEGF-A) expression in dental pulp after application of CaCO3 from Anadara granosa shell.

Material and methods

The thirty Rattus norvegicus strain Wistar used as model. The maxillary first molar was preparation using 0.84 mm low-speed diamond bur to made cavity. The cavity then applied glass ionomer cement (as control group) and other group applied CaCO3 from Anadara granosa shell. The teeth in each group were extracted after 1st, 3rd and 7th days of application for immunohistochemistry analysis for NF-kB, TGF-β1, and VEGF-A expression.

Result

The NF-kB expression in the group with CaCO3 from Anadara granosa shell lower than control after 1st, 3rd and 7th days (p < 0.05). In other hand, the TGF-β1 and VEGF-A expression in the group with CaCO3 from Anadara granosa shell higher than control after 1st, 3rd and 7th days (p < 0.05).

Conclusion

CaCO3 from Anadara granosa shell able to stimulate the TGF-β1 and VEGF-A and suppress the NF-kB expression in the dental pulp. This material able to develop as dentin-pulp material restoration.

Oral biosciences: The annual review 2022

BACKGROUND

The Journal of Oral Biosciences is devoted to advancing and disseminating fundamental knowledge concerning every aspect of oral biosciences.

HIGHLIGHT

This review features review articles in the fields of "Bone Cell Biology," "Tooth Development & Regeneration," "Tooth Bleaching," "Adipokines," "Milk Thistle," "Epithelial-Mesenchymal Transition," "Periodontitis," "Diagnosis," "Salivary Glands," "Tooth Root," "Exosome," "New Perspectives of Tooth Identification," "Dental Pulp," and "Saliva" in addition to the review articles by the winner of the "Lion Dental Research Award" ("Plastic changes in nociceptive pathways contributing to persistent orofacial pain") presented by the Japanese Association for Oral Biology.

CONCLUSION

The review articles in the Journal of Oral Biosciences have inspired its readers to broaden their knowledge about various aspects of oral biosciences. The current editorial review introduces these exciting review articles.

Tampon Vital Pulp Therapy in the Management of Excessive Haemorrhage in Inflamed Pulps: A Hypothesis

Current principles in vital pulp therapy (VPT) modalities emphasise the importance of haemostasis and normal clotting in the achievement of successful treatment outcomes. However, the aforementioned notion could be challenged by the new and recent emerging evidence; suggesting that prolonged or excessive bleeding/haemorrhage (PB) in cases of intensly inflamed pulps, conventionally infamous as irreversible pulpitis (IP), may not impede the healing potential of the remaining dental pulp tissue following VPTs using endodontic biomaterials. "Tampon VPT (tVPT)" may be considered a treatment approach for the management of stated IP cases; characterised by severe pulpal inflammation and delayed clotting process. The presented hypothesis evaluates clinical studies, experimental research and molecular impacts on clotting within the inflamed dental pulp, so as to explore the efficacy as well as the safety of tVPT as a viable treatment option. Latest clinical investigations have reported positive outcomes with tVPT; even in the presence of IP with PB. It has been shown that inflamed dental pulp tissues exhibit molecular impacts on the clotting cascade, which may contribute to the delayed clotting process. Nonetheless, the healing capacity of the dental pulp is not negatively affected by hyperaemia. Additionally, enhanced blood flow in the inflamed pulpal tissues may be associated with improved healing and boosted hard tissue formation. Moreover, tVPT could possibly promote pulpal healing and/or regeneration through continuing the presentation of essential nutrients, e.g. oxygen, and growth factors to the injured tissue. Furthermore, increased blood flow may facilitate the recruitment of immune and reparative cells; promoting tissue repair and encouraging the formation of dentinal bridge(s) after VPTs. Consequently, the state-of-the-art research and their findings could support the hypothesis that tVPT may effectively manage IP cases with PB and contribute to favourable outcomes.

Dentin regeneration based on tooth tissue engineering: A review

Missing or damaged teeth due to caries, genetic disorders, oral cancer, or infection may contribute to physical and mental impairment that reduces the quality of life. Despite major progress in dental tissue repair and those replacing missing teeth with prostheses, clinical treatments are not yet entirely satisfactory, as they do not regenerate tissues with natural teeth features. Therefore, much of the focus has centered on tissue engineering (TE) based on dental stem/progenitor cells to create bioengineered dental tissues. Many in vitro and in vivo studies have shown the use of cells in regenerating sections of a tooth or a whole tooth. Tooth tissue engineering (TTE), as a promising method for dental tissue regeneration, can form durable biological substitutes for soft and mineralized dental tissues. The cell-based TE approach, which directly seeds cells and bioactive components onto the biodegradable scaffolds, is currently the most potential method. Three essential components of this strategy are cells, scaffolds, and growth factors (GFs). This study investigates dentin regeneration after an injury such as caries using TE and stem/progenitor cell-based strategies. We begin by discussing about the biological structure of a dentin and dentinogenesis. The engineering of teeth requires knowledge of the processes that underlie the growth of an organ or tissue. Then, the three fundamental requirements for dentin regeneration, namely cell sources, GFs, and scaffolds are covered in the current study, which may ultimately lead to new insights in this field.

Caffeic Acid Phenethyl Ester Induces Vascular Endothelial Growth Factor Production and Inhibits CXCL10 Production in Human Dental Pulp Cells

The survival rate of root non-vital teeth is lower than that of vital teeth. Therefore, to preserve the dental pulp is very important. The vascular endothelial growth factor (VEGF) is the most potent angiogenic factor involved in the vitality of dental pulp including reparative dentin formation. Caffeic acid phenethyl ester (CAPE) is a physiologically active substance of propolis and has some bioactivities such as anti-inflammatory effects. However, there are no reports on the effects of CAPE on dental pulp inflammation. In this study, we investigated the effects of CAPE on VEGF and inflammatory cytokine production in human dental pulp cells (HDPCs) to apply CAPE to an ideal dental pulp protective agent. We found that CAPE induced VEGF production from HDPCs. Moreover, CAPE induced the phosphorylation of p38 mitogen-activated protein kinase (MAPK), extracellular signal-regulated kinases (ERK), and stress-activated protein kinase/c-Jun N-terminal kinase (SAP/JNK) in HDPCs. Furthermore, CAPE inhibited C-X-C motif chemokine ligand 10 (CXCL10) production in Pam3CSK4- and tumor necrosis factor-alpha (TNF-α)-stimulated HDPCs. In conclusion, these results suggest that CAPE might be useful as a novel biological material for vital pulp therapy by exerting the effects of VEGF production and anti-inflammatory activities.

The hypoxia-dependent angiogenic process in dental pulp

BACKGROUND

In this review, we analyzed the existing literature to elucidate how the hypoxia-dependent angiogenic processes work in dental pulp. Angiogenesis is an essential biological process in the maturation and homeostasis of teeth. It involves multiple sequential steps such as endothelial cell proliferation and migration, cell-to-cell contact, and tube formation.

HIGHLIGHT

Clinical implications of understanding the process of angiogenesis include how the mineralization processes of dental pulp occur and how dental pulp maintains its homeostasis, preventing irreversible inflammation or necrosis.

CONCLUSION

The angiogenesis process in dental pulp regulates adequate concentrations of oxygen required for mineralization in root development and defense mechanisms against chronic stimuli.

Different Sources of Mesenchymal Stem Cells for Tissue Regeneration: A Guide to Identifying the Most Favorable One in Orthopedics and Dentistry Applications

The success of regenerative medicine in various clinical applications depends on the appropriate selection of the source of mesenchymal stem cells (MSCs). Indeed, the source conditions, the quality and quantity of MSCs, have an influence on the growth factors, cytokines, extracellular vesicles, and secrete bioactive factors of the regenerative milieu, thus influencing the clinical result. Thus, optimal source selection should harmonize this complex setting and ensure a well-personalized and effective treatment. Mesenchymal stem cells (MSCs) can be obtained from several sources, including bone marrow and adipose tissue, already used in orthopedic regenerative applications. In this sense, for bone, dental, and oral injuries, MSCs could provide an innovative and effective therapy. The present review aims to compare the properties (proliferation, migration, clonogenicity, angiogenic capacity, differentiation potential, and secretome) of MSCs derived from bone marrow, adipose tissue, and dental tissue to enable clinicians to select the best source of MSCs for their clinical application in bone and oral tissue regeneration to delineate new translational perspectives. A review of the literature was conducted using the search engines Web of Science, Pubmed, Scopus, and Google Scholar. An analysis of different publications showed that all sources compared (bone marrow mesenchymal stem cells (BM-MSCs), adipose tissue mesenchymal stem cells (AT-MSCs), and dental tissue mesenchymal stem cells (DT-MSCs)) are good options to promote proper migration and angiogenesis, and they turn out to be useful for gingival, dental pulp, bone, and periodontal regeneration. In particular, DT-MSCs have better proliferation rates and AT and G-MSC sources showed higher clonogenicity. MSCs from bone marrow, widely used in orthopedic regenerative medicine, are preferable for their differentiation ability. Considering all the properties among sources, BM-MSCs, AT-MSCs, and DT-MSCs present as potential candidates for oral and dental regeneration.

Galloylated proanthocyanidins in dentin matrix exhibit biocompatibility and induce differentiation in dental stem cells

Aim

Grape seed extract contains a complex mixture of proanthocyanidins (PACs), a plant biopolymer used as a biomaterial to improve reparative and preventive dental therapies. Co-polymerization of PACs with type I collagen mechanically reinforces the dentin extracellular matrix. This study assessed the biocompatibility of PACs from grape seed extract on dental pulp stem cells (DPSCs) in a model simulating leaching through dentin to the pulp cavity. The aim was to determine the type of PACs (galloylated vs. non-galloylated) within grape seed extract that are most compatible with dental pulp tissue.

Methodology

Human demineralized dentin was treated with selectively-enriched dimeric PACs prepared from grape seed extract using liquid-liquid chromatography. DPSCs were cultured within a 2D matrix and exposed to PAC-treated dentin extracellular matrix. Cell proliferation was measured using the MTS assay and expression of odontoblastic genes was analyzed by qRT-PCR. Categorization of PACs leaching from dentin was performed using HPLC-MS.

Results

Enriched dimeric fractions containing galloylated PACs increased the expression of certain odontoblastic genes in DPSCs, including Runt-related transcription factor 2 (RUNX2), vascular endothelial growth factor (VEGF), bone morphogenetic protein 2 (BMP2), basic fibroblast growth factor (FGF2), dentin sialophosphoprotein (DSPP) and collagen, type I, alpha 1 (COLI). Galloylated dimeric PACs also exhibited minor effects on DPSC proliferation, resulting in a decrease compared to control after five days of treatment. The non-galloylated dimer fraction had no effect on these genes or on DPSC proliferation.

Conclusions

Galloylated PACs are biocompatible with DPSCs and may exert a beneficial effect on cells within dental pulp tissue. The observed increase in odontoblastic genes induced by galloylated PACs together with a decrease in DPSC proliferation is suggestive of a shift toward cell differentiation. This data supports the use of dimeric PACs as a safe biomaterial, with galloylated dimeric PACs exhibiting potential benefits to odontoblasts supporting dentin regeneration.

Wnt Signalling in Regenerative Dentistry

Teeth are complex structures where a soft dental pulp tissue is enriched with nerves, vasculature and connective tissue and encased by the cushioning effect of dentin and the protection of a hard enamel in the crown and cementum in the root. Injuries such as trauma or caries can jeopardise these layers of protection and result in pulp exposure, inflammation and infection. Provision of most suitable materials for tooth repair upon injury has been the motivation of dentistry for many decades. Wnt signalling, an evolutionarily conserved pathway, plays key roles during pre- and post-natal development of many organs including the tooth. Mutations in the components of this pathway gives rise to various types of developmental tooth anomalies. Wnt signalling is also fundamental in the response of odontoblasts to injury and repair processes. The complexity of tooth structure has resulted in diverse studies looking at specific compartments or cell types of this organ. This review looks at the current advances in the field of tooth development and regeneration. The objective of the present review is to provide an updated vision on dental biomaterials research, focusing on their biological properties and interactions to act as evidence for their potential use in vital pulp treatment procedures. We discuss the outstanding questions and future directions to make this knowledge more translatable to the clinics.

An In Vitro Study of the Effects of Crocin on the Modulation of DSPP, VEGF-A, HLA-G5, STAT3 and CD200 Expression in Human Dental Pulp Stem Cells

Dental pulp stem cells (DPSCs) have been recommended as promising candidate for cell-based therapeutic applications due to high potentials in tissue repair/regeneration and modulation of immune responses. The gene expression change strategy by natural plant enhancers is an available opportunity to improve the stemness properties of these cells. The objective of this research was the evaluation of Crocin effects (saffron plant's bioactive compound) on immunoregulation and tissue regeneration-related biomarkers expression in human DPSCs. Based on the results of cell viability assay, application of 400 μM and lower concentrations of Crocin had no toxic effects on DPSCs; however, the time-dependent cytotoxic effects were observed at higher concentrations. This study, probably for the first time, detected the surface expression of CD200 in DPSCs with a slight time-dependent upward trend and reported that treatment with Crocin could increase expression of this macromolecule up to many times over. Also, it revealed that this carotenoid significantly led to the time-dependent upregulation of dentin sialophosphoprotein, vascular endothelial growth factor A, human leukocyte antigen-G5, and signal transducer and activator of transcription-3 messenger ribonucleic acids (mRNAs); however, this significant upregulation for STAT3 occurred, followed by a remarkable reduction. The results of this study indicated that cell treatment with Crocin may be effective in improving the stemness capacities of DPSCs. Therefore, the study provided basis for more insights into the biological effects of Crocin on DPSCs that it may aid in the future improvement of mesenchymal stem cell-based therapies.

Evaluation of vascular endothelial growth factor - A release from platelet-rich fibrin, platelet-rich fibrin matrix, and dental pulp at different time intervals

Background

Lack of collateral blood supply and the low compliance environment of pulp makes its healing, a challenge. Vascular endothelial growth factor (VEGF) is a primary angiogenic growth factor. Knowledge of dose and time-dependent expression of VEGF from platelet concentrates, namely platelet-rich fibrin (PRF) and PRF matrix (PRFM), along with vital pulp can aid in developing strategies to improve the outcome of vital pulp therapy and regenerative procedures. Hence, the aim of this study was to compare VEGF kinetics of PRF, PRFM, and dental pulp.

Materials and Methods

The PRF, PRFM, and vital dental pulp were placed in culture media for a week; the supernatant was collected from these samples at days 1, 4, and 7. VEGF-A expression was evaluated using ELISA and compared with the weight of the sample so as to quantify the release of VEGF-A per milligram of sample.

Results

PRF exhibited maximum VEGF-A release on day 4 and was sustained till day 7. In contrast, PRFM and dental pulp showed no significant release of VEGF-A till day 7. However, on day 7, there was a rapid increase in VEGF-A expression from dental pulp that was comparable to PRF. On comparing the release of VEGF-A per milligram of tissue, pulp exhibited the maximum values.

Conclusion

Among the platelet concentrates, differential expression of VEGF-A was superior in PRF. The use of PRF in partial pulpitis should be explored in order to restore pulp vascularity and hasten pulpal healing.

Effect of Intracanal Medicaments and Irrigants on the Release of Transforming Growth Factor Beta 1 and Vascular Endothelial Growth Factor from Cervical Root Dentin

INTRODUCTION

This study aimed to evaluate (1) the effect of irrigating solutions and intracanal medicaments on the release of transforming growth factor beta 1 (TGF-β1) and vascular endothelial growth factor (VEGF) from cervical root dentin and (2) the effect of associating triple antibiotic paste (TAP) and calcium hydroxide paste (CH) with 2% chlorhexidine (CHX) on TGF-β1 release.

METHODS

First, 119 specimens from roots (cervical thirds) were obtained and were distributed into 5 groups: 2% CHX, 2.5% sodium hypochlorite, TAP, CH, and 10% EDTA by each growth factor (TGF-β1 [n = 8] and VEGF [n = 8]). Then, specimens were distributed as follows (n = 13): TAP + 2% CHX, CH + 2% CHX, and 10% EDTA and treated with irrigating solutions and intracanal medicaments. After the treatments, the specimens were immersed in 10% EDTA (20 minutes), and the solution was analyzed using the enzyme-linked immunosorbent assay. The data were submitted to normality, homogeneity of variance, and Mann-Whitney tests (P < .05).

RESULTS

Significant differences were found between the irrigating solutions (P < .05) and intracanal medicaments for TGF-β1 (P < .05). No VEGF release was detected for any group. Our results showed no significant differences among the TAP + 2% CHX and EDTA groups for TGF-β1 but a significant difference between CH + 2% CHX and the other groups (P < .05).

CONCLUSIONS

The use of 2% CHX as the irrigating solution, CH as the intracanal medicament, and 10% EDTA as the final irrigation provides higher TGF-β1 release from the cervical root dentin, whereas VEGF was not detected. Moreover, TAP and 2% CHX with 10% EDTA as the final irrigation resulted in greater TGF-β1 release from cervical root dentin than CH + 2% CHX.

Caffeic Acid Phenethyl Ester (CAPE) Induces VEGF Expression and Production in Rat Odontoblastic Cells

Caffeic acid phenethyl ester (CAPE), the main component of propolis, has various biological activities including anti-inflammatory effect and wound healing promotion. Odontoblasts located in the outermost layer of dental pulp play crucial roles such as production of growth factors and formation of hard tissue termed reparative dentin in host defense against dental caries. In this study, we investigated the effects of CAPE on the upregulation of vascular endothelial growth factor (VEGF) and calcification activities of odontoblasts, leading to development of novel therapy for dental pulp inflammation caused by dental caries. CAPE significantly induced mRNA expression and production of VEGF in rat clonal odontoblast-like KN-3 cells cultured in normal medium or osteogenic induction medium. CAPE treatment enhanced nuclear factor-kappa B (NF-κB) transcription factor activation, and furthermore, the specific inhibitor of NF-κB significantly reduced VEGF production. The expression of VEGF receptor- (VEGFR-) 2, not VEGFR-1, was up regulated in KN-3 cells treated with CAPE. In addition, VEGF significantly increased mineralization activity in KN-3 cells. These findings suggest that CAPE might be useful as a novel biological material for the dental pulp conservative therapy.

Evaluation of Chitosan Hydrogel for Sustained Delivery of VEGF for Odontogenic Differentiation of Dental Pulp Stem Cells

The pulpotomy with pulp capping is aimed at retaining vital pulp with reparative dentin formation. Vascular endothelial growth factor (VEGF) plays a crucial role in dentin regeneration; however, its constant administrations in the human body is still problematic. Chitosan was widely studied as an effective carrier to deliver bioactive molecules in regenerative medicine. In this study, we conducted a chitosan/β-glycerophosphate (CS/β-GP) hydrogel as a VEGF-sustained release system and explored its effects on dental pulp stem cells (DPSCs). CS/β-GP hydrogel was manufactured using a sol-gel method. SEM assay showed the spongy and porous microstructure of the lyophilized hydrogels. DPSCs cultured in the CS/β-GP hydrogel kept adhesion and vitality. CCK-8 assay tested the promoted proliferation activity of DPSCs on the hydrogel. Besides, the added VEGF protein could continually release from VEGF/CS/β-GP hydrogel. The VEGF/CS/β-GP hydrogel could promote the odontogenic differentiation of DPSCs better than VEGF treatment without hydrogel. Our results suggested that CS/β-GP hydrogel could continually release VEGF and contribute to odontogenic differentiation of DPSCs, thus may become a potential carrier of bioactive molecules in pulp capping therapy.

Effect of recombinant vascular endothelial growth factor and translationally controlled tumor protein on 2‑hydroxyethyl methacrylate‑treated pulp cells

Vascular endothelial growth factor (VEGF)-A is a potential signaling protein that may promote angiogenesis. VEGF also helps cells survive in stressfull or hazardous conditions. The present study aimed to compare the effect of VEGF with translationally controlled tumor protein (TCTP), an anti‑apoptotic protein in human dental pulp cells (HDPCs), following exposure to 2‑hydroxyethyl methacrylate (HEMA), which is a major residual monomer from resin restorative dental materials. Cell viability, alkaline phosphatase (ALP) activity, mineralization and gene expressions for odontogenic and osteogenic differentiation markers of HDPCs were investigated, following exposure to HEMA and in combination with TCTP and VEGF. The results revealed that TCTP at 1 ng/ml and VEGF at 10 ng/ml significantly promoted the proliferation of HDPCs (P<0.05). TCTP (1 ng/ml) and VEGF (10 ng/ml) maintained the cell viability of 4 mM HEMA‑treated cells at the same percentage as the control. However, cells treated with HEMA+TCTP+VEGF had a lower cell viability than the groups treated with HEMA and TCTP or VEGF alone. TCTP and VEGF promoted cell proliferation, ALP activity and mineralization, and upregulated of DSPP, DMP‑1, BMP‑2, and ALP mRNA expression compared with the control. Furthermore, the HEMA+TCTP and HEMA+VEGF groups had significantly higher percentages of calcium deposition than HEMA‑treated cells (P<0.001). HEMA was cytotoxic to HDPCs, reduced ALP activity and caused the significant downregulation of odontogenic and osteogenic gene expressions (P<0.05). It was concluded that VEGF and TCTP promoted pulp cell growth and the survival of HEMA‑treated cells without synergistic effects. TCTP was required in lower concentrations for these effects. VEGF and TCTP enhanced cell differentiation and mineralization.

Leptin Induces Odontogenic Differentiation and Angiogenesis in Human Dental Pulp Cells via Activation of the Mitogen-activated Protein Kinase Signaling Pathway

INTRODUCTION

Up-regulation of odontogenic differentiation, dentin formation, and angiogenesis in dental pulp are key factors in vital pulp therapy. The aim of this study was to investigate whether leptin could promote odontogenic differentiation and angiogenesis in human dental pulp cells (hDPCs). In addition, the involvement of the intracellular signaling pathway in these effects was determined.

METHODS

The viability of hDPCs treated with leptin was examined using the water soluble tetrazolium salt-1 assay. Real-time polymerase chain reaction was performed to determine messenger RNA (mRNA) expression levels of odontogenic and angiogenic markers. Western blot analysis was used to measure odontogenic and angiogenic protein expression levels and assess mitogen-activated protein kinase (MAPK) pathway involvement. Alkaline phosphatase (ALP) and alizarin red staining were used to evaluate expression levels of ALP and calcified nodule formation after treatment with leptin and/or the presence of MAPK inhibitors.

RESULTS

All concentrations of leptin used in this study did not significantly affect the viability of hDPCs. However, mRNA and protein levels of odontogenic and angiogenic markers, ALP activity, and calcified nodule formation were significantly increased in the leptin-treated group compared with those in the control group. Leptin enhanced phosphorylation of extracellular signal-related kinases, c-Jun N-terminal kinase, and p38 mitogen-activated protein kinases within 5 minutes after treatment. However, leptin-induced dentin sialophosphoprotein and vascular endothelial growth factor protein expression and mineralization were appreciably blocked by the presence of MAPK inhibitors.

CONCLUSIONS

Leptin can induce angiogenesis, odontogenic differentiation, and mineralization in hDPCs via activating the MAPK signaling pathway.

IGF-1 Mediates EphrinB1 Activation in Regulating Tertiary Dentin Formation

Eph receptors belong to a subfamily of receptor tyrosine kinases that are activated by membrane-spanning ligands called ephrins. Previously, we demonstrated that the ephrinB1-EphB2 interaction regulates odontogenic/osteogenic differentiation from dental pulp cells (DPCs) in vitro. The goal of this study was to identify the molecular mechanisms regulated by the EphB2/ephrinB1 system that govern tertiary dentin formation in vitro and in vivo. During tooth development, ephrinB1, and EphB2 were expressed in preodontoblast and odontoblasts at postnatal day 4. EphrinB1 was continuously expressed in odontoblasts and odontoblastic processes until the completion of tooth eruption. In addition, ephrinB1 was expressed in odontoblastic processes 2 wk following tooth injury without pulp exposure, whereas EphB2 was expressed in the center of pulp niches but not odontoblasts. In a model of tooth injury with pulp exposure, ephrinB1 was strongly expressed in odontoblasts 4 wk postinjury. In vitro studies with human and mouse DPCs treated with calcium hydroxide (CH) or mineral trioxide aggregate (MTA) showed an increased expression of insulin-like growth factor 1 (IGF-1). Experiments using several inhibitors of IGF-1 receptor signaling revealed that inhibiting the Ras/Raf-1/MAPK pathway inhibited EphB2 expression, and inhibiting the PI3K/Akt/mTOR pathway specifically inhibited ephrinB1 gene expression. Tooth injury in mice with odontoblast-specific IGF-1 receptor ablation exhibited a reduced tertiary dentin volume, mineral density, and ephrinB1 expression 4 wk following injury. We conclude that the IGF-1/ephrinB1 axis plays significant roles in the early stages of tooth injury. Further research is needed to fully understand the potential of targeting ephrinB1 as a regenerative pulp therapy.

Therapeutic potential of dental stem cells

Stem cell biology has become an important field in regenerative medicine and tissue engineering therapy since the discovery and characterization of mesenchymal stem cells. Stem cell populations have also been isolated from human dental tissues, including dental pulp stem cells, stem cells from human exfoliated deciduous teeth, stem cells from apical papilla, dental follicle progenitor cells, and periodontal ligament stem cells. Dental stem cells are relatively easily obtainable and exhibit high plasticity and multipotential capabilities. The dental stem cells represent a gold standard for neural-crest-derived bone reconstruction in humans and can be used for the repair of body defects in low-risk autologous therapeutic strategies. The bioengineering technologies developed for tooth regeneration will make substantial contributions to understand the developmental process and will encourage future organ replacement by regenerative therapies in a wide variety of organs such as the liver, kidney, and heart. The concept of developing tooth banking and preservation of dental stem cells is promising. Further research in the area has the potential to herald a new dawn in effective treatment of notoriously difficult diseases which could prove highly beneficial to mankind in the long run.

Characterization of a Vascular Endothelial Growth Factor-loaded Bioresorbable Delivery System for Pulp Regeneration

INTRODUCTION

Vascular endothelial growth factor (VEGF) is a signal protein that stimulates angiogenesis and vasculogenesis and has been used in tissue regeneration and pulp regeneration experimental models. The purpose of this study was to develop a delivery system composed of a biodegradable fiber and controlled release of VEGF to promote cell viability and secure an adequate blood supply for the survival of human stem cells of the apical papilla (SCAP) favoring endodontic regenerative procedures.

METHODS

We developed a polydioxanone fiber, 50 μm in diameter, loaded with VEGF at a linear concentration of 12.2 ng/cm. Cytotoxic effects of the VEGF-loaded fiber (VF) on SCAP and mouse fibroblasts were assessed by using a multiparametric assay kit (XTT-NR-CVDE [Xenometrix, Allschwil, Switzerland]). We evaluated VF-induced mRNA expression of downstream growth factors by using a human growth factor Taqman array in real-time polymerase chain reaction. We also assessed the in vivo subcutaneous reaction of C57BL/6 mice to implants of VF alone and human root fragments (10 mm in length) filled with VF after 10, 20, and 45 days. Statistical analyses were performed by using analysis of variance and Student t tests or non-parametric alternatives.

RESULTS

Enzyme-linked immunosorbent assay verified detectable concentrations of released VEGF in solution for 25 days. No cytotoxicity was observed on SCAP and mouse fibroblasts treated with VEGF. In addition, VEGF treatment also induced the expression of additional growth factors with roles in tissue and blood vessel formation and neuroprotective function. Implantation of VF and root fragments filled with VF showed biocompatibility in vivo, promoting new blood vessels and connective tissue formation into the root canal space with negligible inflammation.

CONCLUSIONS

Our results show that the VF used in this study is biocompatible and may be a promising scaffold for additional optimization and use in endodontic regenerative procedures.