An in vitro anti-inflammatory effect of Thai propolis in human dental pulp cells.

OBJECTIVE: To explore the potential for development of Thai propolis extract as a pulp capping agent to suppress pulpal inflammation from dental pulp infections. This study aimed to examine the anti-inflammatory effect of the propolis extract on the arachidonic acid pathway, activated by interleukin (IL)-1ß, in cultured human dental pulp cells. METHODOLOGY: Dental pulp cells, isolated from three freshly extracted third molars, were first characterized for their mesenchymal origin and treated with 10 ng/ml of IL-1ß in the presence or absence of non-toxic concentrations of the extract from 0.08 to 1.25 mg/ml, as determined by the PrestoBlue cytotoxic assay. Total RNA was harvested and analyzed for mRNA expressions of 5-lipoxygenase (5-LOX) and cyclooxygenase-2 (COX-2). Western blot hybridization was performed to investigate COX-2 protein expression. Culture supernatants were assayed for released prostaglandin E2 levels. Immunofluorescence was conducted to determine involvement of nuclear factor-kappaB (NF-kB) in the inhibitory effect of the extract. RESULTS: Stimulation of the pulp cells with IL-1ß resulted in the activation of arachidonic acid metabolism via COX-2, but not 5-LOX. Incubation with various non-toxic concentrations of the propolis extract significantly inhibited upregulated COX-2 mRNA and protein expressions upon treatment with IL-1ß (p<0.05), resulting in a significant decrease in elevated PGE2 levels (p<0.05). Nuclear translocation of the p50 and the p65 subunits of NF-kB upon treatment with IL-1ß was also blocked by incubation with the extract. CONCLUSIONS: Upregulated COX-2 expression and enhanced PGE2 synthesis upon treatment with IL-1ß in human dental pulp cells were suppressed by incubation with non-toxic doses of Thai propolis extract via involvement of the NF-kB activation. This extract could be therapeutically used as a pulp capping material due to its anti-inflammatory properties.

Nano eggshell-based slurry as a direct pulp-capping material: In vitro characterization and histopathological assessment in an experimental animal model.

AIM: Pulp vitality is essential for tooth integrity. Following pulp exposure, choosing a suitable pulp-capping material is crucial to maintain pulp vitality. However, the reparative dentine bridge created by calcium hydroxide (Ca(OH)2 ) is generally porous and incomplete. The aim of the current study is to assess the in vitro and in vivo bioactivities of nano eggshell-based slurry (NES), using NES as a direct pulp-capping material, compared with Ca(OH)2 in rabbit animal model. METHODOLOGY: Nano eggshell powder (NE) was characterized for particle morphology, chemical composition and ion release. In vitro bioactivity was tested by immersion in simulated body fluid (SBF) for 7 days. For histopathological evaluation, 36 adult New Zealand rabbits (72 pulp exposures) were divided into nine groups (n = 8) according to the pulp-capping material (NES, Ca(OH)2 and no capping as negative control group) and the animals were sacrificed after 7, 14 or 28 days. The pulps of the two lower central incisors were exposed and then directly capped by Ca(OH)2 or NES or left untreated. The cavities were then sealed with glass ionomer cement. Teeth were collected for histopathological evaluation using an optical microscope. Pulp haemorrhage, inflammation, fibrosis and calcific bridge formation were assessed. Results were statistically analysed using anova and Tukey's tests. RESULTS: Nano eggshell particles were spherical with a 20 nm diameter and were composed mainly of calcite. Statistical analysis showed that there was a significant increase in the release of all investigated ions between days 1 and 28, except for copper. NES group showed a significantly higher release of all elements as compared to Ca(OH)2 . Environmental scanning electron microscope micrographs of NES incubated for 7 days in SBF showed the formation of HAp with a Ca/P ratio (1.686). For histopathological evaluation, the difference between groups was statistically significant. At day 28, 75% of the pulps of the Ca(OH)2 group showed mild calcific bridge in comparison with 100% moderate calcific bridge in the NES group. The NES group showed significantly less inflammation at days 7 and 28, and higher fibrosis at day 7 compared with Ca(OH)2 . CONCLUSIONS: Nano eggshell-based slurry represents a promising novel direct pulp-capping material with favourable pulp tissue response.

The Potential Application of Human Gingival Fibroblast-Conditioned Media in Pulp Regeneration: An In Vitro Study.

Regenerative endodontic treatment based on tissue engineering has recently gained interest in contemporary restorative dentistry. However, low survival rates and poor potential differentiation of stem cells could undermine the success rate of pulp regenerative therapy. Human gingival fibroblast-conditioned medium (hGF-CM) has been considered a potential therapy for tissue regeneration due to its stability in maintaining multiple factors essential for tissue regeneration compared to live cell transplantation. This study aimed to investigate the potency of hGF-CM on stem cells from human dental pulp (DPSC) in pulp regeneration. A series of experiments confirmed that hGF-CM contributes to a significant increase in proliferation, migration capability, and cell viability of DPSC after H2O2 exposure. Moreover, it has been proved to facilitate the odontogenic differentiation of DPSC via qRT-PCR, ALP (alkaline phosphatase), and ARS (Alizarin Red S) staining. It has been discovered that such highly upregulated odontogenesis is related to certain types of ECM proteins (collagen and laminin) from hGF-CM via proteomics. In addition, it is found that the ERK pathway is a key mechanism via inhibition assay based on RNA-seq result. These findings demonstrate that hGF-CM could be beneficial biomolecules for pulp regeneration.

Influence of violet LED associated or not with peroxide gel on inflammation, mineralization, and collagen fiber maturation in dentin and pulp tissue.

OBJECTIVES: To evaluate the influence of violet LED, associated or not with a 17.5% hydrogen peroxide (HP) bleaching gel, on inflammation, mineralization in pulp tissue, and collagen fiber maturation in dentin and pulp tissue. MATERIALS AND METHODS: The maxillary molars of eighty Wistar rats were distributed into four groups (n = 10): CONT - without treatment; HP - 30 min application of 17.5% HP; LED - 20 min application of violet LED; and HP+LED - application of PH and violet LED. Rats were euthanized and jaws were processed for histologic and immunohistochemical evaluation (IL-17, IL-23, and osteocalcin) and picrosirius red immediately after (T0), and at 7 (T1), 15 (T2), and 30 days (T3) post-treatment, with Wilcoxon, Mann-Whitney, paired T-test, and T-test (α = 0.05). RESULTS: HP and HP+LED presented necrosis and severe inflammatory infiltrate. When compared to CONT group, LED presented severe osteocalcin (OCN) immunostaining in T2 and less immature fibers in T2 and T3. CONCLUSION: The violet LED caused no severe damage to the pulp tissue, increased IL-17 and IL-23 expression in T0 when associated with HP, and had no influence on pulp tissue mineralization, besides accelerating the maturation of collagen fibers of dentin. CLINICAL RELEVANCE: Violet LED therapy induced no inflammation in the pulp tissue of rats and played no role in pulp tissue fibrosis, besides accelerating the maturation of dentin collagen fibers.

In vitro evaluation of injectable Tideglusib-loaded hyaluronic acid hydrogels incorporated with Rg1-loaded chitosan microspheres for vital pulp regeneration.

Injectable systems receive attention in endodontics due to the complicated and irregular anatomical structure of root canals. Here, injectable Tideglusib (Td)-loaded hyaluronic acid hydrogels (HAH) incorporated with Rg1-loaded chitosan microspheres (CSM) were developed for vital pulp regeneration, providing release of Td and Rg1 to trigger odontoblastic differentiation of human dental pulp stem cells (DPSC) by Td and vascularization of pulp by Rg1. The optimal concentrations were determined as 90 nM and 50 µg/mL for Td and Rg1, and loaded in HA and CSM in HAH, respectively. Odontogenic (COL1A1, ALP, OCN, Axin-2, DSPP, and DMP1) and angiogenic (VEGFA, VEGFR2, and eNOS) differentiation of DPSC cultured in the presence of hydrogels was shown at gene expression level. Our results suggest that our injectable hydrogel formulation has potential to improve strategies for vital pulp regeneration. In vivo evaluations are needed to test the feasibility and potential of these hydrogels for vital pulp regeneration.

Novel Bioactive Adhesive Monomer CMET Promotes Odontogenic Differentiation and Dentin Regeneration.

This study aimed to evaluate the in vitro effect of the novel bioactive adhesive monomer CMET, a calcium salt of 4-methacryloxyethyl trimellitate acid (4-MET), on human dental pulp stem cells (hDPSCs) and its capacity to induce tertiary dentin formation in a rat pulp injury model. Aqueous solutions of four tested materials [4-MET, CMET, Ca(OH)2, and mineral trioxide aggregate (MTA)] were added to the culture medium upon confluence, and solvent (dH2O) was used as a control. Cell proliferation was assessed using the Cell Counting Kit-8 assay, and cell differentiation was evaluated by real-time quantitative reverse transcription-polymerase chain reaction. The mineralization-inducing capacity was evaluated using alizarin red S staining and an alkaline phosphatase activity assay. For an in vivo experiment, a mechanical pulp exposure model was prepared on Wistar rats; damaged pulp was capped with Ca(OH)2 or CMET. Cavities were sealed with composite resin, and specimens were assessed after 14 and 28 days. The in vitro results showed that CMET exhibited the lowest cytotoxicity and highest odontogenic differentiation capacity among all tested materials. The favorable outcome on cell mineralization after treatment with CMET involved p38 and c-Jun N-terminal kinases signaling. The nuclear factor kappa B pathway was involved in the CMET-induced mRNA expression of odontogenic markers. Similar to Ca(OH)2, CMET produced a continuous hard tissue bridge at the pulp exposure site, but treatment with only CMET produced a regular dentinal tubule pattern. The findings suggest that (1) the evaluated novel bioactive adhesive monomer provides favorable biocompatibility and odontogenic induction capacity and that (2) CMET might be a very promising adjunctive for pulp-capping materials.

Simvastatin treatment promotes proliferation of human dental pulp stem cells via modulating PI3K/AKT/miR-9/KLF5 signalling pathway.

Simvastatin serves as an effective therapeutic potential in the treatment of dental disease via alternating proliferation of dental pulp stem cells. First, western-blot and real-time quantitative PCR were used to detect the effect of simvastatin or LY294002 on the expression levels of AKT, miR-9 and KLF5, or determine the effect of miR-9. Simvastatin, KLF5 and AKT significantly enhanced the proliferation of pulp stem cells, whilst this effect induced by simvastatin was suppressed by LY294002, AKT siRNA, KLF5 siRNA and miR-9, and simvastatin dose-dependently upregulated the expression of PI3K. Furthermore, simvastatin upregulated PI3K and p-AKT expression in a concentration-dependent manner. LY294002 abrogated the upregulation of p-AKT expression levels induced by simvastatin, and LY294002 induced the miR-9 expression and simvastatin dose-dependently inhibited the expression of miR-9, by contrast, LY294002 reduced the KLF5 expression and simvastatin dose-dependently promoted the expression of KLF5. And using computational analysis, KLF5 was found to be a candidate target gene of miR-9, and which was further verified using luciferase assay. Finally, the level of KLF5 in cells was much lower following the transfection with miR-9 and KLF5 siRNA, and the level of AKT mRNA in cells was significantly inhibited after transfection with AKT siRNA than control. These findings suggested simvastatin could promote the proliferation of pulp stem cells, possibly by suppressing the expression of miR-9 via activating the PI3K/AKT signalling pathway, and the downregulation of miR-9 upregulated the expression of its target gene, KLF5, which is directly responsible for the enhanced proliferation of pulp stem cells.

The protective effects of S14G-humanin (HNG) against lipopolysaccharide (LPS)- induced inflammatory response in human dental pulp cells (hDPCs) mediated by the TLR4/MyD88/NF-κB pathway.

Pulpitis is reported in large populations of patients and significantly impacts their normal life quality. It is reported that the lipopolysaccharide (LPS) in Gram-negative bacteria induces severe inflammation in dental pulp tissues. S14G-humanin is a derivative of humanin and has been recently confirmed to possess promising anti-inflammatory properties. The current study aims to explore the possibility of treating pulpitis with S14G-humanin. LPS-stimulated dental pulp cells (DPCs) were utilized to simulate an inflammatory state in the progression of pulpitis. We found the elevated expressions and production of interleukin- 6 (IL-6), tumor necrosis factor-α (TNF-α), macrophage chemoattractant protein-1 (MCP-1), matrix metalloproteinase-2 (MMP-2), and matrix metalloproteinase-9 (MMP-9), upregulated Pentraxin 3 (PTX3) and activated oxidative stress in LPS-treated DPCs were all reversed by treatment with 50 and 100 µM S14G-humanin. In addition, the LPS-induced elevated expression levels of toll-like receptor 4 (TLR4) and myeloid differentiation primary response 88 (Myd88), and activation of the IκBα/NF-κB signaling pathway in hDPCs were significantly repressed by treatment with S14G-humanin. Conclusively, we found that S14G-humanin protected LPS-treated hDPCs by inhibiting the TLR4/MyD88/NF-κB signaling pathway.

H2O2 gel bleaching induces cytotoxicity and pain conduction in dental pulp stem cells via intracellular reactive oxygen species on enamel/dentin disc.

BACKGROUND: Bleaching is widely accepted for improving the appearance of discolored teeth; however, patient compliance is affected by bleaching-related complications, especially bleaching sensitivity. This study aimed to investigate the role of reactive oxygen species (ROS) in cytotoxicity and pain conduction activated by experimental tooth bleaching. METHODS: Dental pulp stem cells with or without N-acetyl-L-cysteine (NAC), an ROS scavenger, were cultured on the dentin side of the enamel/dentin disc. Subsequently, 15% (90 min) and 40% (30 min) bleaching gels were painted on the enamel surface. Cell viability, intracellular ROS, Ca2+, adenosine triphosphate (ATP), and extracellular ATP levels were evaluated using the Cell Counting Kit-8 assay, 2',7'-dichlorodihydrofluorescein diacetate, CellROX, fura-3AM fluorescence assay, and ATP measurement kit. The rat incisor model was used to evaluate in vivo effects after 0, 1, 3, 7, and 30 days of bleaching. Changes in gene and protein expression of interleukin 6 (IL-6), tumor necrosis factor-alpha (TNFα), transient receptor potential ankyrin 1 (TRPA1), and Pannexin1 (PANX1) in dental pulp stem cells and pulp tissue were detected through RT-PCR, western blotting, and immunofluorescence. RESULTS: The bleaching gel suppressed dental pulp stem cell viability and extracellular ATP levels and increased intracellular ROS, Ca2+, and intracellular ATP levels. The mRNA and protein expression of IL-6, TNFα, TRPA1, and PANX1 were up-regulated in vitro and in vivo. Furthermore, the 40% gel had a stronger effect than the 15% gel, and NAC ameliorated the gel effects. CONCLUSIONS: Our findings suggest that bleaching gels induce cytotoxicity and pain conduction in dental pulp stem cells via intracellular ROS, which may provide a potential therapeutic target for alleviating tooth bleaching nociception.

Interleukin-10 Modulates the Metabolism and Osteogenesis of Human Dental Pulp Stem Cells.

The osteogenic differentiation of mesenchymal stem cells (MSCs) is strongly related with the inflammatory microenvironment. The ability of osteogenic differentiation of MSCs is vital for the bone tissue engineering. Interleukin (IL)-10, a well-known anti-inflammatory factor, plays a key role in tissue repair. Dental pulp stem cells (DPSCs), with the advantage of convenience of extraction, are suitable for the bone tissue engineering. Therefore, it is meaning to explore the effects of IL-10 on the osteogenic differentiation of DPSCs. The proliferation activity of DPSCs were evaluated by MTS assay (CellTiter 96® Aqueous One Solution Cell Proliferation Assay [Promega]) and real-time polymerase chain reaction (RT-PCR). The osteogenic differentiation of DPSCs were determined by Alizarin Red staining, RT-PCR, and alkaline phosphatase activity test. The glucose metabolism was detected by Mito Stress test and glycolysis assay. IL-10 (10 or 20 nM) could enhance the osteogenic differentiation of DPSCs and promoted the metabolic switch from glycolysis to oxidative phosphorylation (OXPHOS), whereas IL-10 (5 and 50 nM) has no obvious effects on the osteogenic differentiation of DPSCs. The OXPHOS inhibitor restrained the promotion of osteogenic differentiation induced by IL-10. These findings show that IL-10 can promote the osteogenesis of DPSCs through the activation of OXPHOS, which provides a potential way for enhancing the osteogenic differentiation of DPSCs in bone tissue engineering.

TRPA1 triggers hyperalgesia and inflammation after tooth bleaching.

Hyperalgesia has become a major problem restricting the clinical application of tooth bleaching. We hypothesized that transient receptor potential ankyrin 1 (TRPA1), a pain conduction tunnel, plays a role in tooth hyperalgesia and inflammation after bleaching. Dental pulp stem cells were seeded on the dentin side of the disc, which was cut from the premolar buccal tissue, with 15% (90 min) or 40% (3 × 15 min) bleaching gel applied on the enamel side, and treated with or without a TRPA1 inhibitor. The bleaching gel stimulated intracellular reactive oxygen species, Ca2+, ATP, and extracellular ATP in a dose-dependent manner, and increased the mRNA and protein levels of hyperalgesia (TRPA1 and PANX1) and inflammation (TNFα and IL6) factors. This increment was adversely affected by TRPA1 inhibitor. In animal study, the protein levels of TRPA1 (P = 0.0006), PANX1 (P < 0.0001), and proliferation factors [PCNA (P < 0.0001) and Caspase 3 (P = 0.0066)] increased significantly after treated rat incisors with 15% and 40% bleaching gels as detected by immunohistochemistry. These results show that TRPA1 plays a critical role in sensitivity and inflammation after tooth bleaching, providing a solid foundation for further research on reducing the complications of tooth bleaching.

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.

Dual antioxidant-photosensitizing hydrogel system: Cross-linking of chitosan with tannic acid for enhanced photodynamic efficacy.

Herein, a new antioxidant-photosensitizing hydrogel based on chitosan has been developed to control photodynamic therapy (PDT) activity in cancer treatment. In PDT, photosensitizers generate reactive oxygen species (ROS) during photochemical reactions, leading oxidative damage to cancer cells. However, high ROS levels are lethal to non-target healthy cells and tissues such as endothelial cells and blood cells. To mediate these drawbacks, we improved PDT with a natural polyphenolic antioxidant, Tannic acid (TA), to control the ROS level and minimize side effects through singlet oxygen (1O2) scavenging. In this work, chitosan-based hydrogels were designed using tannic acid as an antioxidant cross-linker and loaded with water-soluble N, N'-di-(l-alanine)-3,4,9,10-perylene tetracarboxylic diimide (PDI-Ala) as a photosensitizer. Our results showed that the hydrogel formed a three-dimensional (3D) microstructure with good mechanical strength and significant singlet oxygen production and antioxidant activity. In addition, the behavior of human melanoma cell line A375 and dental pulp stem cells (as normal cells) was compared and studied during an in vitro photodynamic treatment. Normal cells had a higher viability than cancer cells, indicating that the PDT is more effective on cancer cells than on normal cells. The new hydrogels could be applied as an effective new drug to control PDT performance.

Effect of treatment with resiniferatoxin in an experimental model of pulpal inflammatory in mice.

AIM: To evaluate whether treatment with resiniferatoxin (RTX) is capable of lowering the plasma levels of PGE2 and TNF-α, as well as histopathological parameters in inflammation of pulp tissue in a mouse experimental model. METHODOLOGY: Ten groups of six BALB/c mice were formed as follows: healthy group (HC ), healthy group treated with RTX (HRTX ), two groups with pulp inflammation at 14 and 18 hours (PI14 /PI18 ), six groups with pulpal inflammation plus treatment with Ibuprofen (IBU14 /IBU18 ), dexamethasone (DEX14 /DEX18 ) and resiniferatoxin (RTX14 /RTX18 ) at 14 and 18 hours, respectively. Pulpal inflammation was induced through occlusal exposure of the pulp of the maxillary first molar. The plasma levels of PGE2 and TNF-α and the histological parameters of the pulp tissue of the HC and HRTX groups were evaluated at the time of acquiring the animals. In the other groups, the plasma levels of PGE2 and TNF-α and the histopathological parameters were evaluated at 14 and 18 hours after pulp damage. Plasma levels of PGE2 and TNF-α were quantified by ELISA, and the histopathological parameters were evaluated by H/E staining. Statistical significance was determined by one-way analysis of variance (ANOVA) to test for overall differences between group means. RESULTS: A significant increase (*p < .05) in plasma levels of PGE2 and TNF-α occurred 14 and 18 hours after pulp damage. In addition, treatment with RTX significantly decreased (*p < .05) the plasma levels of PGE2 and TNF-α at 14 and 18 hours after pulp damage, as well as the infiltrate of inflammatory cells at 18 hours after pulp damage, similarly to treatment with ibuprofen and dexamethasone. CONCLUSION: It was possible to detect systemic levels of PGE2 and TNF-α at 14 and 18 hours after pulp damage. Likewise, treatment with RTX was associated with an anti-inflammatory effect similar to treatment with ibuprofen and dexamethasone. These findings place resiniferatoxin as a therapeutic alternative in the treatment of inflammatory diseases in Dentistry.

Taxifolin Protects Dental Pulp Stem Cells under Hypoxia and Inflammation Conditions.

BACKGROUND: Dental pulp stem cells (DPSCs) are a unique source for future clinical application in dentistry such as periodontology or endodontics. However, DPSCs are prone to apoptosis under abnormal conditions. Taxifolin is a natural flavonoid and possesses many pharmacological activities including anti-hypoxic and anti-inflammatory. We aimed to elucidate the mechanisms of taxifolin protects DPSC under hypoxia and inflammatory conditions. METHODS: DPSCs from human dental pulp tissue was purchased from Lonza (cat. no. PT-5025. Basel, Switzerland)) and identified by DPSC's biomarkers. DPSC differentiation in vitro following the manufacturers' instructions. ARS staining and Oil red staining verify the efficiency of differentiation in vitro after 2 weeks. The changes of various genes and proteins were identified by Q-PCR and western-blot, respectively. Cell viability was determined by the CCK-8 method, while apoptosis was determined by Annexin V/PI staining. RESULTS: DPSC differentiation in vitro shows that hypoxia and TNF-α synergistically inhibit the survival and osteogenesis of DPSCs. A final concentration of 10 µM Taxifolin can significantly reduce the apoptosis of DPSCs under inflammation and hypoxia conditions. Taxifolin substantially increases carbonic anhydrase IX (CA9) expression but not HIF1a, and inhibitions of CA9 expression nullify the protective role of taxifolin under hypoxia and inflammatory condition. CONCLUSION: Taxifolin significantly increased the expression of CA9 when it inhibits DPSC apoptosis and taxifolin synergistically to protect DPSCs against apoptosis with CA9 under hypoxia and inflammatory conditions. Taxifolin can be used as a potential drug for clinical treatment of DPSC-related diseases.

Immunomodulatory effects of phytosomal curcumin on related-micro RNAs, CD200 expression and inflammatory pathways in dental pulp stem cells.

Human dental pulp stem cells (hDPSCs) have significant potential of immunomodulatory for therapeutic and regenerative biomedical applications compared to other mesenchymal stem cells (MSCs). Nowadays, alteration of gene expression is an important way to improve the performance of MSCs in the clinic. MicroRNAs (miRs) and CD200 are known to modulate the immune system in MSCs. Curcumin is famous for its anti-inflammatory impacts. Phytosomal curcumin (PC) is a nanoparticle synthesized from curcumin that removes the drawbacks of curcumin. The purpose of this research was to assess the effects of PC on the expression of the CD200 and four key miRNAs in immune system. PC (30 µM) treatment of hDPSCs could ameliorate their immunoregulatory property, presented by reduced expressions of miR-21, miR-155 and miR-126, as well as enhanced expressions of miR-23 and CD200. The PC was also able to reduce PI3K\AKT1\NF-κB expressions that were target genes for these miRs and involved in inflammatory pathways. Moreover, PC was more effective than curcumin in improving the immune modulation of hDPSCs. Evidence in this study suggested that PC mediates immunoregulatory activities in hDPSC via miRs and CD200 to regulate PI3K\AKT1\NF-κB signalling pathways, which may provide a theoretical basis for PC in the treatment of many diseases. SIGNIFICANCE OF THE STUDY: Autoimmune diseases or tooth caries are partly attributed to global health problems and their common drug treatments have several side effects. The goal of this study is dentin regeneration and autoimmune diseases treatment via stem cell-based approaches with phytosomal curcumin (PC), for the first time. Because dental pulp stem cells have unique advantages (including higher immunomodulatory capacity) over other mesenchymal stem cells, we considered them the best option for treating these diseases. Using PC, we try to increase the immunomodulatory properties of these cells.

Compromised dental cells viability following teeth-whitening exposure.

This study aimed to assess the viability of dental cells following time-dependent carbamide peroxide teeth-whitening treatments using an in-vitro dentin perfusion assay model. 30 teeth were exposed to 5% or 16% CP gel (4 h daily) for 2-weeks. The enamel organic content was measured with thermogravimetry. The time-dependent viability of human dental pulp stem cells (HDPSCs) and gingival fibroblast cells (HGFCs) following either indirect exposure to 3 commercially available concentrations of CP gel using an in-vitro dentin perfusion assay or direct exposure to 5% H2O2 were investigated by evaluating change in cell morphology and by hemocytometry. The 5% and 16% CP produced a significantly lower (p < 0.001) enamel protein content (by weight) when compared to the control. The organic content in enamel varied accordingly to the CP treatment: for the 16% and 5% CP treatment groups, a variation of 4.0% and 5.4%, respectively, was observed with no significant difference. The cell viability of HDPSCs decreased exponentially over time for all groups. Within the limitation of this in-vitro study, we conclude that even low concentrations of H2O2 and CP result in a deleterious change in enamel protein content and compromise the viability of HGFCs and HDPSCs. These effects should be observed in-vivo.

Effect of Inducible BMP-7 Expression on the Osteogenic Differentiation of Human Dental Pulp Stem Cells.

BMP-7 has shown inductive potential for in vitro osteogenic differentiation of mesenchymal stem cells, which are an ideal resource for regenerative medicine. Externally applied, recombinant BMP-7 was able to induce the osteogenic differentiation of DPSCs but based on our previous results with BMP-2, we aimed to study the effect of the tetracyclin-inducible BMP-7 expression on these cells. DPSC, mock, and DPSC-BMP-7 cell lines were cultured in the presence or absence of doxycycline, then alkaline phosphatase (ALP) activity, mineralization, and mRNA levels of different osteogenic marker genes were measured. In the DPSC-BMP-7 cell line, the level of BMP-7 mRNA significantly increased in the media supplemented with doxycycline, however, the expression of Runx2 and noggin genes was upregulated only after 21 days of incubation in the osteogenic medium with doxycycline. Moreover, while the examination of ALP activity showed reduced activity in the control medium containing doxycycline, the accumulation of minerals remained unchanged in the cultures. We have found that the induced BMP-7 expression failed to induce osteogenic differentiation of DPSCs. We propose three different mechanisms that may worth investigating for the engineering of expression systems that can be used for the induction of differentiation of mesenchymal stem cells.

Immunomodulatory Expression of Cathelicidins Peptides in Pulp Inflammation and Regeneration: An Update.

The role of inflammatory mediators in dental pulp is unique. The local environment of pulp responds to any changes in the physiology that are highly fundamental, like odontoblast cell differentiation and other secretory activity. The aim of this review is to assess the role of cathelicidins based on their capacity to heal wounds, their immunomodulatory potential, and their ability to stimulate cytokine production and stimulate immune-inflammatory response in pulp and periapex. Accessible electronic databases were searched to find studies reporting the role of cathelicidins in pulpal inflammation and regeneration published between September 2010 and September 2020. The search was performed using the following databases: Medline, Scopus, Web of Science, SciELO and PubMed. The electronic search was performed using the combination of keywords "cathelicidins" and "dental pulp inflammation". On the basis of previous studies, it can be inferred that LL-37 plays an important role in odontoblastic cell differentiation and stimulation of antimicrobial peptides. Furthermore, based on these outcomes, it can be concluded that LL-37 plays an important role in reparative dentin formation and provides signaling for defense by activating the innate immune system.

The Effect of Calcium-Silicate Cements on Reparative Dentinogenesis Following Direct Pulp Capping on Animal Models.

Dental pulp vitality is a desideratum for preserving the health and functionality of the tooth. In certain clinical situations that lead to pulp exposure, bioactive agents are used in direct pulp-capping procedures to stimulate the dentin-pulp complex and activate reparative dentinogenesis. Hydraulic calcium-silicate cements, derived from Portland cement, can induce the formation of a new dentin bridge at the interface between the biomaterial and the dental pulp. Odontoblasts are molecularly activated, and, if necessary, undifferentiated stem cells in the dental pulp can differentiate into odontoblasts. An extensive review of literature was conducted on MedLine/PubMed database to evaluate the histological outcomes of direct pulp capping with hydraulic calcium-silicate cements performed on animal models. Overall, irrespective of their physico-chemical properties and the molecular mechanisms involved in pulp healing, the effects of cements on tertiary dentin formation and pulp vitality preservation were positive. Histological examinations showed different degrees of dental pulp inflammatory response and complete/incomplete dentin bridge formation during the pulp healing process at different follow-up periods. Calcium silicate materials have the ability to induce reparative dentinogenesis when applied over exposed pulps, with different behaviors, as related to the animal model used, pulpal inflammatory responses, and quality of dentin bridges.