Effects of epigallocatechin gallate (EGCG) on the biological properties of human dental pulp stem cells and inflammatory pulp tissue

Design and evaluation of an MMP-9-responsive hydrogel for vital pulp therapy

OBJECTIVE

To design and evaluate a matrix metalloproteinase 9 (MMP-9)-responsive hydrogel for vital pulp therapy.

METHODS

A peptide linker with optimized sensitivity toward MMP-9 was crosslinked with 4-arm poly (ethylene glycol)-norbornene (PEG-NB) by thiol-norbornene photo-polymerization. This resulted in the formation of a hydrogel network in which the peptide IDR-1002 was incorporated. Hydrogel characterization and gelation kinetics were examined with Fourier-transform infrared spectroscopy, scanning electron microscopy, rheological testing, and swelling evaluation. Hydrogel degradation was examined through multiple exposure to pre-activated MMP-9, to simulate flare-ups of dental pulp inflammation. The IDR-1002 released from degraded hydrogels was measured with high-performance liquid chromatography. Effect of IDR-1002 released from hydrogels on one-week-old multispecies oral biofilms was evaluated using confocal laser scanning microscopy.

RESULTS

MMP-9-responsive, injectable, and photo-crosslinkable hydrogels were successfully synthesized. When hydrogel degradation and release of IDR-1002 were examined with exposure to pre-activated MMP-9, IDR-1002 release was significantly correlated with elevated levels of MMP-9 (p < 0.05). The effectiveness of IDR-1002 in killing bacteria in multispecies oral biofilms was significantly enhanced when the hydrogels were immersed in 10 nM or 20 nM pre-activated MMP-9, compared to immersion in phosphate-buffered saline (p < 0.05).

CONCLUSIONS

The MMP-9-responsive hydrogel is a promising candidate for on-demand delivery of bioactive agent in vital pulp therapy.

CLINICAL SIGNIFICANCE

MMP-9 is one of the most important diagnostic and prognostic biomarkers for pulpitis. An MMP-9-responsive hydrogel has potential to be used as an in-situ on-demand release system for the diagnosis and treatment of dental pulp inflammation.

Data-driven dentistry: Computational revelations redefining pulp capping

Introduction

Pulpal and periradicular diseases stem from immune reactions to microbiota, causing inflammation. Limited blood supply hampers dental pulp self-healing. Managing inflammation involves eliminating bacteria and reducing pro-inflammatory mediators especially MMP-9, which has a significant correlation with pulpitis. s. Flavonoids like Hesperidin, Baicalein, Epigallocatechin gallate, Genistein, Icariin, and Quercetin show potential for pulp capping.

Aim

This in-silico study compares various Flavonoids for their anti-inflammatory effects on MMP-9, with Chlorhexidine as a control, a known MMP-9 inhibitor.

Materials and Methods

Protein and Ligand Preparation: The human MMP-9 catalytic domain (PDB ID: 4XCT) structure was retrieved, and necessary modifications were made. Flavonoids from PubChem database were prepared for docking using AutoDock Vina. A grid for docking was created, and molecular dynamics simulations were conducted using Gromacs-2019.4 with GROMOS96 force field. Trajectory analysis was performed, and MM-PBSA calculation determined binding free energies.

Results

Analysis of MMP-9 and ligand interactions revealed Hesperidin's high binding affinity, forming numerous hydrogen bonds with specific amino acids. Molecular dynamics simulations confirmed stability, with RMSD, RMSF, Rg, and SASA indicating consistent complex behaviour over 100 ns. MM-PBSA calculation affirmed favourable energy contributions in MMP-9-Hesperidin interactions.

Conclusion

MMP-9 plays a crucial role in prognosis of pulpitis. Incorporating MMP-9 inhibitors into pulp capping agents may enhance therapeutic efficacy. Hesperidin emerges as a potent MMP-9 inhibitor, warranting further in vivo validation against other agents.

Epigallocatechin-3-gallate/mineralization precursors co-delivery hollow mesoporous nanosystem for synergistic manipulation of dentin exposure

As a global public health focus, oral health plays a vital role in facilitating overall health. Defected teeth characterized by exposure of dentin generally increase the risk of aggravating oral diseases. The exposed dentinal tubules provide channels for irritants and bacterial invasion, leading to dentin hypersensitivity and even pulp inflammation. Cariogenic bacterial adhesion and biofilm formation on dentin are responsible for tooth demineralization and caries. It remains a clinical challenge to achieve the integration of tubule occlusion, collagen mineralization, and antibiofilm functions for managing exposed dentin. To address this issue, an epigallocatechin-3-gallate (EGCG) and poly(allylamine)-stabilized amorphous calcium phosphate (PAH-ACP) co-delivery hollow mesoporous silica (HMS) nanosystem (E/PA@HMS) was herein developed. The application of E/PA@HMS effectively occluded the dentinal tubules with acid- and abrasion-resistant stability and inhibited the biofilm formation of Streptococcus mutans. Intrafibrillar mineralization of collagen fibrils and remineralization of demineralized dentin were induced by E/PA@HMS. The odontogenic differentiation and mineralization of dental pulp cells with high biocompatibility were also promoted. Animal experiments showed that E/PA@HMS durably sealed the tubules and inhibited biofilm growth up to 14 days. Thus, the development of the E/PA@HMS nanosystem provides promising benefits for protecting exposed dentin through the coordinated manipulation of dentin caries and hypersensitivity.

"Efficacy of cytotoxic effect of green tea catechins on the human periodontal fibroblasts and human dental pulp fibroblasts -An in vitro study"

Background

Inflammation of tooth-supporting tissue and the pulp tissue is followed by wound healing and regeneration process that involves the specific type of connective tissue cells, the fibroblasts. During periodontitis and pulpitis, the inflammation of the tissue causes damage to the fibroblasts. These fibroblasts secrete collagen proteins and maintain the structural framework; along with this the inflammatory process moves toward healing where in the specific cells such as the fibroblast cells play important roles. Green tea catechins epigallocatechin-3-gallate (EGCG) being one of the major catechins is known to have multiple beneficial effects on human fibroblasts.

Objective

To assess the in vitro cytotoxicity of green tea catechins on the human periodontal ligament (PDL) fibroblasts and human dental pulp fibroblasts.

Materials and Methods

Human PDL fibroblasts (hPDLFs) and human dental pulp fibroblasts were isolated from the two extracted premolar teeth that were indicated for orthodontic treatment. The fibroblasts were then seeded in 96 well tissue culture plate for cell viability study. EGCG was used at different concentration to treat the cells. After 48 h; (3-(4,5-Dimethylthiazol-2-yl)-2,5-Diphenyltetrazolium Bromide) (MTT) assay was performed to determine the cell viability.

Results

The vitality of hPDLFs and human dental pulp fibroblasts was found to be inversely proportional to EGCG concentrations.

Conclusions

hPDLFs have shown 37% proliferation at lowest concentration of EGCG used and human dental pulp fibroblasts have shown 99% viability at lowest concentration of EGCG used.

EGCG alleviated Mn exposure-caused carp kidney damage via trpm2-NLRP3-TNF-α-JNK pathway: Oxidative stress, inflammation, and tight junction dysfunction

Manganese (Mn), an essential trace metal element in organisms. However, with extensive use of Mn in industry and agriculture, Mn becomes a heavy metal pollutant in water. (-)-epigallocatechin gallate (EGCG), an tea polyphenols, can alleviate metal toxicity. Kidney is an important detoxifying organ, but toxic mechanism of Mn to kidneys is unclear, which needs further research. Carp is an Asian important economical species for fisheries and a biological model for studying environmental toxicology. Thus, we established excess Mn and EGCG-supplemented carp model to explore molecular mechanism of EGCG alleviating Mn-caused carp kidney damage. In this experiment, we set a control group (the Con group), a Mn treatment group (the Mn group, 90 mg/L Mn), a EGCG supplement group (the EG group, 75 mg/kg EGCG), and a combined group (the Mn + EG group, 90 mg/L Mn and 75 mg/kg EGCG). Transcriptome, qRT-PCR, kit, and morphology method results indicated that excess Mn caused oxidative stress, inflammatory damage, and tight junction dysfunction in carp kidneys. Excess Mn-triggered oxidative stress caused tight junction dysfunction via trpm2-NLRP3-TNF-α-JNK pathway and inflammation. EGCG reversed the harm of Mn to fish through the above mechanism. The findings of this study provided the evidence of EGCG-alleviated Mn poisoning and offered new ideas for reducing heavy metal environmental pollution risk.

Effect of HM-Exos on the migration and inflammatory response of LPS-exposed dental pulp stem cells

AIM

The purpose of this study was to investigate the effects of human milk exosomes (HM-Exos) on the viability, migration, and inflammatory responses of lipopolysaccharide (LPS)-exposed human dental pulp stem cells (HDPSCs) in vitro.

METHODS

HM-Exos were isolated, and dynamic light scattering (DLS), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) were used to analyze their physical properties (size and shape). To construct an in vitro inflammation model, HDPSCs were exposed to LPS. The MTT test and migration assay were used to investigate the effect of HM-Exos on cell proliferation and migration, and the quantitative polymerase chain reaction (qPCR) was used to assess the expression of inflammatory genes in HDPSCs. Data were analyzed using a one-way analysis of variance (ANOVA) with Tukey's post-test.

RESULTS

DLS measurement revealed that HM-Exos were 116.8 ± 3.6 nm in diameter. The SEM and TEM images revealed spherical shapes with diameters of 97.2 ± 34.6 nm. According to the results of the cell viability assay, the nontoxic concentration of HM-Exos (200 µg/ml) was chosen for the subsequent investigations. The migration assay results showed that HM-Exos improved the potential of LPS-exposed HDPSCs to migrate. The qPCR results indicated that HM-Exos significantly reduced the expression of inflammatory cytokines such as TNF-α, IL-1β, and IL-6 in HDPSCs after LPS stimulation.

CONCLUSIONS

HM-Exos increased LPS-exposed HDPSCs migration and proliferation and reduced gene expression of inflammatory cytokines. They may be a viable candidate for pulpitis therapy.

Natural Bioactive Epigallocatechin-Gallate Promote Bond Strength and Differentiation of Odontoblast-like Cells

The (-)-Epigallocatechin-gallate (EGCG) metabolite is a natural polyphenol derived from green tea and is associated with antioxidant, biocompatible, and anti-inflammatory effects.

OBJECTIVE

To evaluate the effects of EGCG to promote the odontoblast-like cells differentiated from human dental pulp stem cells (hDPSCs); the antimicrobial effects on Escherichia coli, Streptococcus mutans, and Staphylococcus aureus; and improve the adhesion on enamel and dentin by shear bond strength (SBS) and the adhesive remnant index (ARI).

MATERIAL AND METHODS

hDSPCs were isolated from pulp tissue and immunologically characterized. EEGC dose-response viability was calculated by MTT assay. Odontoblast-like cells were differentiated from hDPSCs and tested for mineral deposition activity by alizarin red, Von Kossa, and collagen/vimentin staining. Antimicrobial assays were performed in the microdilution test. Demineralization of enamel and dentin in teeth was performed, and the adhesion was conducted by incorporating EGCG in an adhesive system and testing with SBS-ARI. The data were analyzed with normalized Shapiro-Wilks test and ANOVA post hoc Tukey test.

RESULTS

The hDPSCs were positive to CD105, CD90, and vimentin and negative to CD34. EGCG (3.12 µg/mL) accelerated the differentiation of odontoblast-like cells. Streptococcus mutans exhibited the highest susceptibility < Staphylococcus aureus < Escherichia coli. EGCG increased (p < 0.05) the dentin adhesion, and cohesive failure was the most frequent.

CONCLUSION

(-)-Epigallocatechin-gallate is nontoxic, promotes differentiation into odontoblast-like cells, possesses an antibacterial effect, and increases dentin adhesion.

Green tea catechins inhibit Porphyromonas gulae LPS-induced inflammatory responses in human gingival epithelial cells: Running title

OBJECTIVES

To determine the anti-inflammatory effects of green tea catechins in immortalized human gingival epithelial cells (Ca9-22) stimulated with Porphyromonas gulae lipopolysaccharide (LPS).

METHODS

Ca9-22 cells were incubated with P. gulae LPS (10 μg/ml) with or without green tea catechins, epigallocatechin-3-gallate (EGCg), epigallocatechin (EGC), epicatechin-3-gallate (ECG), and epicatechin (EC) (each at 50 μM), for 6 or 24 hours. Real-time polymerase chain reaction (PCR) and enzyme-linked immunosorbent assay were used to determine the induction of cyclooxygenase 2 (COX2), tumor necrosis factor alpha (TNF-ɑ), interleukin 6 (IL-6), and IL-8. Furthermore, the expression of toll-like receptors (TLRs) 2 and 4 was examined using real-time PCR and western blotting analysis, and phosphorylation of the p38 and ERK1/2 was examined using western blotting analysis.

RESULTS

At the mRNA and protein levels, EGCg, EGC, ECG, and EC were found to significantly inhibit COX2, TNF-ɑ, IL-6, and IL-8. Furthermore, the levels of ERK1/2 and p38 phosphorylation induced by P. gulae LPS were decreased following the addition of each of the catechins, as well as TLR2 and 4 mRNA and protein.

CONCLUSIONS

These findings indicate that green tea catechins are potent inhibitors of inflammatory responses induced by P. gulae LPS, and may also be useful for prevention and/or attenuation of periodontitis.

Analysis of the role and mechanism of EGCG in septic cardiomyopathy based on network pharmacology

Background

Septic cardiomyopathy (SC) is a common complication of sepsis that leads to an increase in mortality. The pathogenesis of septic cardiomyopathy is unclear, and there is currently no effective treatment. EGCG (epigallocatechin gallate) is a polyphenol that has anti-inflammatory, antiapoptotic, and antioxidative stress effects. However, the role of EGCG in septic cardiomyopathy is unknown.

Methods

Network pharmacology was used to predict the potential targets and molecular mechanisms of EGCG in the treatment of septic cardiomyopathy, including the construction and analysis of protein-protein interaction (PPI) network, gene ontology (GO), and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis and molecular docking. The mouse model of septic cardiomyopathy was established after intraperitoneal injection of LPS (lipopolysaccharide). The myocardial protective effect of EGCG on septic mice is observed by cardiac ultrasound and HE staining. RT-PCR is used to verify the expression level of the EGCG target in the septic cardiomyopathy mouse model.

Results

A total of 128 anti-SC potential targets of EGCGareselected for analysis. The GO enrichment analysis and KEGG pathway analysis results indicated that the anti-SC targets of EGCG mainly participate in inflammatory and apoptosis processes. Molecular docking results suggest that EGCG has a high affinity for the crystal structure of six targets (IL-6 (interleukin-6), TNF (tumor necrosis factor), Caspase3, MAPK3 (Mitogen-activated protein kinase 3), AKT1, and VEGFA (vascular endothelial growth factor)), and the experimental verification result showed levated expression of these 6 hub targets in the LPS group, but there is an obvious decrease in expression in the LPS + EGCG group. The functional and morphological changes found by echocardiography and HE staining show that EGCG can effectively improve the cardiac function that is reduced by LPS.

Conclusion

Our results reveal that EGCG may be a potentially effective drug to improve septic cardiomyopathy. The potential mechanism by which EGCG improves myocardial injury in septic cardiomyopathy is through anti-inflammatory and anti-apoptotic effects. The anti-inflammatory and anti-apoptotic effects of EGCG occur not only through direct binding to six target proteins (IL-6,TNF-α, Caspase3, MAPK3, AKT1, and VEGFA) but also by reducing their expression.

Role of Lipopolysaccharide, Derived from Various Bacterial Species, in Pulpitis—A Systematic Review

Lipopolysaccharide (LPS) is widely used for induction of inflammation in various human tissues, including dental pulp. The purpose of this study was to summarize current medical literature focusing on (1) cell types used by researchers to simulate dental pulp inflammation, (2) LPS variants utilized in experimental settings and how these choices affect the findings. Our study was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). We searched for studies reporting outcomes of lipopolysaccharide application on dental pulp cells in vitro using electronic databases: MEDLINE, Web of Science and Scopus. Having gathered data from 115 papers, we aimed to present all known effects LPS has on different cell types present in dental pulp. We focused on specific receptors and particles that are involved in molecular pathways. Our review provides an essential foundation for further research using in vitro models of pulpitis.