Rutin promotes the formation and osteogenic differentiation of human periodontal ligament stem cell sheets in vitro

Periodontal ligament stem cell-based bioactive constructs for bone tissue engineering

Objectives: Stem cell-based tissue engineering approaches are promising for bone repair and regeneration. Periodontal ligament stem cells (PDLSCs) are a promising cell source for tissue engineering, especially for maxillofacial bone and periodontal regeneration. Many studies have shown potent results via PDLSCs in bone regeneration. In this review, we describe recent cutting-edge researches on PDLSC-based bone regeneration and periodontal tissue regeneration. Data and sources: An extensive search of the literature for papers related to PDLSCs-based bioactive constructs for bone tissue engineering was made on the databases of PubMed, Medline and Google Scholar. The papers were selected by three independent calibrated reviewers. Results: Multiple types of materials and scaffolds have been combined with PDLSCs, involving xeno genic bone graft, calcium phosphate materials and polymers. These PDLSC-based constructs exhibit the potential for bone and periodontal tissue regeneration. In addition, various osteo inductive agents and strategies have been applied with PDLSCs, including drugs, biologics, gene therapy, physical stimulation, scaffold modification, cell sheets and co-culture. Conclusoin: This review article demonstrates the great potential of PDLSCs-based bioactive constructs as a promising approach for bone and periodontal tissue regeneration.

Application value of combination therapy of periodontal curettage and root planing on moderate-to-severe chronic periodontitis in patients with type 2 diabetes

BACKGROUND

Our study attempted to observe the value of periodontal curettage combined with root planing on moderate-to-severe chronic periodontitis in patients with type 2 diabetes.

METHODS

There involved 72 patients with type 2 diabetes mellitus complicated with moderate-to-severe chronic periodontitis who were diagnosed and treated in our hospital from January 2019 to December 2019. The patients enrolled were randomly divided into four groups using a computer-generated table: root planing and periodontal curettage combined group (n = 18), root planning group (n = 18), periodontal curettage group (n = 18) and cleansing group (n = 18). Blood glucose, plaque index (PI), gingival index (GI), probing depth (PD), attachment loss (AL), serum levels of inflammatory factors (Tumor Necrosis Factor Alpha [TNF- α] and hypersensitive C-reactive protein [hs-CRP]) were observed before and after treatment. The collecting dates were analyzed by the chi-square χ 2 test, repeated measurement analysis of variance, or t-test according to different data types and research objectives.

RESULTS

Before treatment, there was no significant difference in PI, GI, PD and AL among the four groups (P> 0.05), while after 3-month treatment, the levels of PI, GI, PD and AL in the combined group were lower than those in the root planing group, periodontal curettage group and cleansing group, with both root planing group and periodontal curettage group significantly lower than cleansing group (P< 0.05). The fasting blood glucose, 2-h postprandial blood glucose and glycosylated hemoglobin in the combined group, root planing group, periodontal curettage group and cleansing group were significantly lower than those before treatment (P < 0.05). Before treatment, there was no significant difference in TNF- α and hs-CRP among the four groups (P> 0.05), but the levels of TNF- α and hs-CRP in the four groups decreased significantly after 3-month treatment (P< 0.05). The levels of TNF- α and hs-CRP in the combined group were lower than those in the root planing group, periodontal curettage group and cleansing group, and those in the root planing group and periodontal curettage group were significantly lower than those in the cleansing group (P< 0.05).

CONCLUSION

The combination therapy of periodontal curettage and root planing exerted beneficial effects on moderate-to-severe chronic periodontitis in patients with type 2 diabetes mellitus, which holds the potential to maintain the level of blood glucose and improve the quality of life of the patients.

Molecular Docking Analysis of Flavonoid Compounds with Matrix Metalloproteinase- 8 for the Identification of Potential Effective Inhibitors

Background:

Matrix metalloproteinase-8 (MMP-8) participates in the degradation of different types of collagens in the extracellular matrix and basement membrane. Up-regulation of the MMP-8 has been demonstrated in many disorders including cancer development, tooth caries, periodontal/ peri-implant soft and hard tissue degeneration, and acute/chronic inflammation. Therefore, MMP-8 has become an encouraging target for therapeutic procedures for scientists. We carried out a molecular docking approach to study the binding affinity of 29 flavonoids, as drug candidates, with the MMP-8. Pharmacokinetic and toxicological properties of the compounds were also studied. Moreover, it was attempted to identify the most important amino acids participating in ligand binding based on the degree of each of the amino acids in the ligand-amino acid interaction network for MMP-8.

Methods:

Three-dimensional structure of the protein was gained from the RCSB database (PDB ID: 4QKZ). AutoDock version 4.0 and Cytoscape 3.7.2 were used for molecular docking and network analysis, respectively. Notably, the inhibitor of the protein in the crystalline structure of the 4QKZ was considered as a control test. Pharmacokinetic and toxicological features of compounds were predicted using bioinformatics web tools. Post-docking analyses were performed using BIOVIA Discovery Studio Visualizer version 19.1.0.18287.

Results and Discussions:

According to results, 24 of the studied compounds were considered to be top potential inhibitors for MMP-8 based on their salient estimated free energy of binding and inhibition constant as compared with the control test: Apigenin-7-glucoside, nicotiflorin, luteolin, glabridin, taxifolin, apigenin, licochalcone A, quercetin, isorhamnetin, myricetin, herbacetin, kaemferol, epicatechin, chrysin, amentoflavone, rutin, orientin, epiafzelechin, quercetin-3- rhamnoside, formononetin, isoliquiritigenin, vitexin, catechine, and isoquercitrin. Moreover, His- 197 was found to be the most important amino acid involved in the ligand binding for the enzyme.

Conclusion:

The results of the current study could be used in the prevention and therapeutic procedures of a number of disorders such as cancer progression and invasion, oral diseases, and acute/chronic inflammation. Although, in vitro and in vivo tests are inevitable in the future.

Quercetin reverses TNF‑α induced osteogenic damage to human periodontal ligament stem cells by suppressing the NF‑κB/NLRP3 inflammasome pathway

Quercetin (Quer) is a typical antioxidant flavonoid from plants that is involved in bone metabolism, as well as in the progression of inflammatory diseases. Elevated levels of tumor necrosis factor-α (TNF-α), a typical pro-inflammatory cytokine, can affect osteogenesis. In the present study, TNF-α was used to establish an in vitro model of periodontitis. The effects of Quer on, as well as its potential role in the osteogenic response of human periodontal ligament stem cells (hPDLSCs) under TNF-α-induced inflammatory conditions and the underlying mechanisms were then investigated. Within the appropriate concentration range, Quer did not exhibit any cytotoxicity. More importantly, Quer significantly attenuated the TNF-α induced the suppression of osteogenesis-related genes and proteins, alkaline phosphatase (ALP) activity and mineralized matrix in the hPDLSCs. These findings were associated with the fact that Quer inhibited the activation of the NF-κB signaling pathway, as well as the expression of NLRP3 inflammation-associated proteins in the inflammatory microenvironment. Moreover, the silencing of NLRP3 by small interfering RNA (siRNA) was found to protect the hPDLSCs against TNF-α-induced osteogenic damage, which was in accordance with the effects of Quer. On the whole, the present study demonstrates that Quer reduces the impaired osteogenesis of hPDLSCs under TNF-α-induced inflammatory conditions by inhibiting the NF-κB/NLRP3 inflammasome pathway. Thus, Quer may prove to be a potential remedy against periodontal bone defects.

Molecular docking study of flavonoid compounds for possible matrix metalloproteinase-13 inhibition

OBJECTIVES

Matrix metalloproteinase-13 (MMP-13) has been reported to be involved in different biological processes such as degradation of extracellular matrix proteins, activating or degrading some significant regulatory proteins, wound healing, tissue remodeling, cartilage degradation, bone development, bone mineralization, ossification, cell migration, and tumor cell invasion. Further, MMP-13 participates in many oral diseases such as tooth decay, gingivitis, and degradation of enamel and tissue around the implant. In addition, inhibition of MMP-13 has shown therapeutic properties for Alzheimer's disease (AD). We performed molecular docking to assess the binding affinity of 29 flavonoid compounds with the MMP-13. Additionally, pharmacokinetic and toxicity characteristics of the top-ranked flavonoids were studied. The current study also intended to identify the most important amino acids involved in the inhibition of MMP-13 based on topological feature (degree) in the ligand-amino acid network for MMP-13.

METHODS

Molecular docking and network analysis were studied using AutoDock and Cytoscape software, respectively. Pharmacokinetic and toxicity characteristics of compounds were predicted using bioinformatics web tools.

RESULTS

The results revealed that nine of the studied flavonoids had considerable estimated free energy of binding and inhibition constant: Rutin, nicotiflorin, orientin, vitexin, apigenin-7-glucoside, quercitrin, isoquercitrin, quercitrin-3-rhamnoside, and vicenin-2. Proline-242 was found to be the most important amino acid inhibiting the enzyme.

CONCLUSIONS

The results of the current study may be helpful in the prevention and therapeutic procedures of many disorders such as cancer, tooth caries, and AD. Nevertheless, validation tests are required in the future.