Enhanced Proliferative and Osteogenic Potential of Periodontal Ligament Stromal Cells

Comparative Dental Pulp Stem Cells (DPSCs) and Periodontal Ligament Stem Cells (PDLSCs): Difference in effect of aspirin on osteoblast potential of PDLSCs and DPSCs

Periodontal Ligament Stem Cells (PDLSCs) and Dental Pulp Stem Cells (DPSCs) are mesenchymal stem cells with the ability to self-renew and differentiate into three lineages. One significant advantage of dental stem cells, such as PDLSCs and DPSCs, is their ease of harvest compared to other types of mesenchymal stem cells (MSCs). While MSCs are highly valued in bone tissue engineering, MSCs sourced from dental tissues, such as PDLSCs and DPSCs, offer promising options for periodontal regeneration because they are more easily accessible and can be collected through minimally invasive methods. Currently, PDLSCs and DPSCs exhibit a strong ability to undergo osteogenic differentiation when stimulated by factors such as growth factors, chemicals, and paracrine signaling. It has been shown that aspirin (ASA) can enhance the osteoblastic potential of PDLSCs and DPSCs, although the exact mechanism remains unclear. This article examines the origin and features of mesenchymal stem cells, the bone regeneration potential of DPSCs and PDLSCs, the factors that enhance their osteogenic differentiation, and a comparison of PDLSCs and DPSCs regarding their proliferation and differentiation abilities. Additionally, we will examine the effects of aspirin on PDLSCs and DPSCs. In conclusion, PDLSCs show a greater effect on osteoblast differentiation.

Electroactive membranes enhance in-situ alveolar ridge preservation via spatiotemporal electrical modulation of cell motility

Post-extraction alveolar bone resorption invariably compromises implant placement and aesthetic restoration outcomes. Current non-resorbable membranes exhibit limited efficacy in alveolar ridge preservation (ARP) due to insufficient cell recruitment and osteoinductive capabilities. Herein, we introduce a multifunctional electroactive membrane (PPy-BTO/P(VDF-TrFE), PB/PT) designed to spatiotemporally regulate cell migration and osteogenesis, harmonizing with the socket healing process. Initially, the membrane's endogenous-level surface potential recruits stem cells from the socket. Subsequently, adherent cell-migration-triggered forces generate on-demand piezopotential, stimulating intracellular calcium ion fluctuations and activating the Ca2+/calcineurin/NFAT1 signaling pathway via Cav3.2 channels. This enhances cell motility and osteogenic differentiation predominantly in the coronal socket region, counteracting the natural healing trajectory. The membrane's self-powered energy supply, proportional to cell migration velocity and manifested as nanoparticle deformation, mitigates ridge shrinkage, both independently and in conjunction with bone grafts. This energy-autonomous membrane, based on the spatiotemporal modulation of cell motility, presents a novel approach for in-situ ARP treatment and the development of 4D bionic scaffolds.

Engineered 3D mesenchymal stem cell aggregates with multifunctional prowess for bone regeneration: Current status and future prospects

BACKGROUND

Impaired efficacy of in vitro expanded mesenchymal stem cells (MSCs) is a universal and thorny situation, which cast a shadow on further clinical translation of exogenous MSCs. Moreover, the relatively lengthy healing process, host metabolic heterogeneity and the sophisticated cell recognition and crosstalk pose rigorous challenges towards MSC-based bone regeneration strategies. Three-dimensional (3D) cell aggregates facilitate more robust intercellular communications and cell-extracellular matrix (ECM) interactions, providing a better mimicry of microarchitectures and biochemical milieus in vivo, which is conducive for stemness maintenance and downstream bone formation.

AIM OF REVIEW

This review enunciates the phenotypic features of MSCs in aggregates, which deepens the knowledge of the MSC fate determination in 3D microenvironment. By summarizing current empowerment methods and biomaterial-combined techniques for establishing functionalized MSC aggregates, this review aims to spark innovative and promising solutions for exalting the translational value of MSCs and improve their therapeutic applications in bone tissue repair.

KEY SCIENTIFIC CONCEPTS OF REVIEW

3D aggregates optimize regenerative behaviors of in vitro cultured MSCs including cell adhesion, viability, proliferation, pluripotency and immunoregulation capacity, etc. Biomaterials hybridization endows MSC aggregates with tailored mechanical and biological properties, which offers more possibilities in adapting various clinical scenarios.

Regulation and functional importance of human periodontal ligament mesenchymal stromal cells with various rates of CD146+ cells

Introduction

Mesenchymal stromal cells (MSCs) with high expression of CD146 have superior properties for tissue regeneration. However, high variability in the rate of CD146+ cells among donors is observed. In this study, the possible reasons behind this variability in human periodontal ligament MSCs (hPDL-MSCs) were explored.

Methods

hPDL-MSCs were isolated from 22 different donors, and rates of CD146+ cells were analyzed by flow cytometry. Furthermore, populations with various rates of CD146+ cells were isolated with magnetic separation. The dependency of cell proliferation, viability, cell cycle, and osteogenic differentiation on the rates of CD146+ cells was investigated. Besides, the effects of various factors, like cell density, confluence, and inflammatory environment on the CD146+ rate and expression were analyzed.

Results

The rate of CD146+ cells exhibited high variability between donors, with the percentage of CD146+ cells ranging from 3% to 67%. Higher percentage of CD146+ cells was associated with higher proliferation, presumably due to the higher percentage of cells in the S-phase, and higher osteogenic differentiation potential. Prolonged cell confluence and higher cell seeding density led to the decline in the rate of CD146+ cells. The surface rate of CD146 in hPDL-MSCs was stimulated by the treatment with interleukin-1β and tumor necrosis factor-α, and inhibited by the treatment with interferon-γ.

Conclusion

These results suggest that hPDL-MSCs with high rate of CD146+ cells are a promising subpopulation for enhancing the effectiveness of MSC-based regenerative therapies, however the rate of CD146 is affected by various factors, which must be considered for cell propagation and their potential application in vivo.

Hypoxia-inducible Factor 1α Contributes to Matrix Metalloproteinases 2/9 and Inflammatory Responses in Periodontitis

Periodontitis is a prevalent condition characterized by inflammation and tissue destruction within the periodontium, with hypoxia emerging as a contributing factor to its pathogenesis. Hypoxia-inducible factor 1α (HIF-1α) has a crucial role in orchestrating adaptive responses to hypoxic microenvironments and has been implicated in various inflammatory-related diseases. Understanding the interplay between HIF-1α, matrix metalloproteinases (MMPs), and inflammatory responses in periodontitis could provide insights into its molecular mechanisms. We investigated the relationship between HIF-1α, MMP2, and MMP9 in gingival crevicular fluid (GCF) and periodontal ligament stem cells (PDLSCs) from periodontitis patients. The expression levels of HIF-1α, MMP2, MMP9, and inflammatory factors (IL-6, IL-1β, TNF-α) were assessed using enzyme-linked immunosorbent assay (ELISA) and real-time PCR (RT-PCR). Additionally, osteogenic differentiation of PDLSCs was identified by alkaline phosphatase activity. Significantly elevated levels of HIF-1α, MMP2, and MMP9 were observed in GCF of periodontitis patients compared to controls. Positive correlations were found between HIF-1α and MMP2/MMP9, as well as with IL-6, IL-1β, and TNF-α. Modulation of HIF-1α expression in PDLSCs revealed its involvement in MMP2/9 secretion and inflammatory responses, with inhibition of HIF-1α mitigating these effects. Furthermore, HIF-1α inhibition alleviated the reduction in osteogenic differentiation induced by inflammatory stimuli. Our findings elucidate the regulatory role of HIF-1α in MMP expression, inflammatory responses, and osteogenic differentiation in periodontitis. In conclusion, targeting HIF-1α signaling pathways may offer therapeutic opportunities for managing periodontitis and promoting periodontal tissue regeneration.

The Impact of Ozone on Periodontal Cell Line Viability and Function

Periodontal diseases, including gingivitis and periodontitis, are chronic inflammatory conditions of the teeth' supporting structures that can lead to progressive tissue destruction and loss if left untreated. Basic treatments like scaling and root planing, alone or combined with antimicrobial agents, are the standard of care. However, with the increasing prevalence of antibiotic resistance and the need for new ideas in therapy, adjunctive treatments like ozone therapy have gained attention. Ozone (O3), a triatomic oxygen molecule, is used because of its strong antimicrobial, anti-inflammatory, and regenerative activity and, hence, as a potential tool in periodontal therapy. This review of the use of ozone therapy in periodontal disease breaks down the multifaceted mechanism of ozone therapy, which includes the selective antimicrobial action against biofilm-associated pathogens, immunomodulatory effects on host cells, and stimulation of tissue repair. O3 therapy disrupts microbial biofilms, enhances immune cell function, and promotes healing by activating Nuclear Factor Erythroid 2-Related Factor 2 (Nrf2) and Mitogen-Activated Protein Kinase (MAPK) signaling pathways that regulate oxidative stress, inflammation, and apoptosis. Additional findings include its ability to upregulate growth factors and extracellular matrix proteins, which is significant for periodontal tissue regeneration. This review also discusses the application of O3 therapy in periodontal cell lines, emphasizing its impact on cell viability, proliferation, and differentiation. Advances in periodontal regenerative techniques, combined with the antimicrobial and healing properties of O3, have demonstrated significant clinical benefits. Challenges, including the need for standardized dosages, effective delivery systems, and long-term studies, are also addressed to ensure safe and effective clinical integration. O3 therapy, with its dual antimicrobial and regenerative capabilities, offers an innovative adjunctive approach to periodontal treatment. Future research focusing on optimized protocols and evidence-based guidelines is essential to fully realize its potential in enhancing periodontal health and improving patient outcomes.

Inhibition of soluble epoxide hydrolase reverses bone loss in periodontitis by upregulating EMCN and inhibiting osteoclasts

BACKGROUND

Improving the microenvironment to augment endogenous regenerative potential has emerged as a fundamental concept for stimulating and expediting periodontal tissue repair and regeneration. Previous studies have demonstrated that TPPU, a soluble epoxide hydrolase inhibitor (sEHi), mediates the suppression of inflammatory bone loss in periodontitis models. However, the underlying mechanisms remain largely elusive.

METHODS

In this study, we constructed a human umbilical vein endothelial cell (HUVEC) and periodontal ligament stem cell (PDLSC) coculture system in vitro and tested the anti-inflammatory effect of TPPU under inflammatory conditions. The roles of HIF-1α and Endomucin (EMCN) in the anti-inflammatory effects of TPPU were analyzed. The effects of TPPU on osteogenesis and osteoclastogenesis in cocultured cells were examined. The in vivo periodontitis model further verified the effects of TPPU on inhibiting neutrophil adhesion and inflammation and inhibiting osteoclasts.

RESULTS

Our in vitro experiments demonstrated that TPPU enhances the interaction between mesenchymal stem cells and vascular endothelial cells to enhance anti-inflammatory and osteogenic differentiation effects and revealed a new anti-inflammatory mechanism of TPPU involving the upregulation of EMCN in endothelial cells to prevent lymphocyte recruitment. We also confirmed that TPPU inhibits osteoclast activity. Our in vivo findings showed that TPPU inhibits osteoclast activity and neutrophil adhesion and enhances periodontal tissue repair and regeneration.

CONCLUSIONS

TPPU promotes local regeneration in periodontitis by inhibiting inflammation and bone resorption. Thus, targeting soluble epoxide hydrolase represents an endogenous regenerative strategy for periodontitis treatment.

Functions of Hemp-Induced Exosomes against Periodontal Deterioration Caused by Fine Dust

Although fine dust is linked to numerous health issues, including cardiovascular, neurological, respiratory, and cancerous diseases, research on its effects on oral health remains limited. In this study, we investigated the protective effects of mature hemp stem extract-induced exosomes (MSEIEs) on periodontal cells exposed to fine dust. Using various methods, including microRNA profiling, PCR, flow cytometry, immunocytochemistry, ELISA, and Alizarin O staining, we found that MSE treatment upregulated key microRNAs, such as hsa-miR-122-5p, hsa-miR-1301-3p, and hsa-let-7e-5p, associated with vital biological functions. MSEIEs exhibited three primary protective functions: suppressing inflammatory genes while activating anti-inflammatory ones, promoting the differentiation of periodontal ligament stem cells (PDLSCs) into osteoblasts and other cells, and regulating LL-37 and MCP-1 expression. These findings suggest that MSEIEs have potential as functional biomaterials for applications in pharmaceuticals, cosmetics, and food industries.

Functionalizable bacterial cellulose composite membrane for guided tissue regeneration

This research aims to develop guided tissue regeneration (GTR) membranes from bacterial cellulose (BC), a natural polysaccharide-based biopolymer. A double-layered BC composite membrane was prepared by coating the BC membrane with mixed carboxymethyl cellulose/poly(ethylene oxide) (CMC/PEO) fibers via electrospinning. The CMC/PEO-BC membranes were then characterized for their chemical and physical characteristics. The 8 % (wt/v) CMC/PEO (1:1) aqueous solution yielded well-defined electrospun CMC/PEO nanofibers (125 ± 10 nm) without beads. The CMC/PEO-BC membranes exhibited good mechanical and swelling properties as well as good cytocompatibility against human periodontal ligament cells (hPDLs). Its functionalizability via carboxyl entities in CMC was tested using the calcium-binding domain of plant-derived recombinant human osteopontin (p-rhOPN-C122). As evaluated by enzyme-linked immunosorbent assay, a 98-99 % immobilization efficiency was achieved in a concentration-dependent manner over an applied p-rhOPN-C122 concentration range of 7.5-30 ng/mL. The biological function of the membrane was assessed by determining the expression levels of osteogenic-related gene transcripts using quantitative real-time reverse-transcriptase polymerase chain reaction. Mineralization assay indicated that the p-rhOPN-C122 immobilized CMC/PEO-BC membrane promoted hPDLs osteogenic differentiation. These results suggested that the developed membrane could serve as a promising GTR membrane for application in bone tissue regeneration.

Effects of surface nanomorphology on the senescence of periodontal ligament stem cells

OBJECTIVES

The effect of TiO2 nanotube morphology on the differentiation potency of senescent periodontal ligament stem cells was investigated.

METHODS

Two types of titanium sheets with TiO2 nanotube morphology (20V-NT and 70V-NT) were prepared via anodic oxidation at 20 and 70 V separately, and their surface morphology was observed. Young periodontal ligament stem cells were cultivated in an osteogenic induction medium, and the most effective surface morphology in promoting osteogenic differentiation was selected. RO3306 and Nutlin-3a were used to induce the aging of young periodontal ligament stem cells, and senescent periodontal ligament stem cells were obtained. The osteogenic differentiation of senescent periodontal ligament stem cells was induced, and the effect of surface morphology on osteogenic differentiation was observed.

RESULTS

Nanotube morphology was achieved on the surfaces of titanium sheets through anodic oxidation, and the diameters of the nanotubes increased with voltage. A significant difference in the effect of nanotube morphology was found among nanotubes with different diameters in the young periodontal ligament stem cells. The surface nanotube morphology of 20V-NT had a more significant effect that promoted osteogenic differentiation. Compared with a smooth titanium sheet, the surface nanotube morphology of 20V-NT increased the number of alkaline phosphatase-positive senescent periodontal ligament stem cells and promoted calcium deposition and the expression of osteogenic marker genes Runt-related transcription factor 2, osteopontin, and osteocalcin.

CONCLUSIONS

A special nanotube morphology enhances the differentiation ability of senescent periodontal ligament stem cells, provides an effective method for periodontal regeneration, and further improves the performance of implants.

The effect of adjunctive LASER application on periodontal ligament stem cells

Periodontal regeneration involves the composite action of cell, scaffolds and signaling molecules. There are numerous autologous sources of regenerative cells which are present close to the vicinity of the periodontally debilitated site, the primary one being the periodontal ligament stem cell, which is believed to have a key role in regeneration. Various methods can be harnessed to optimize and enhance the regenerative potential of PDLSCs such as the application of LASERs. In the last few years there have been various studies which have evaluated the effect of different types of LASERs on PDLSCs and the present review summarizes the photo-biomodulative activity of LASERs in general and its beneficial role in the stimulation of PDLSC specifically.

New Insights in Hydrogels for Periodontal Regeneration

Periodontitis is a destructive inflammatory disease characterized by microbial infection that damages the tissues supporting the tooth (alveolar bone, gingiva, periodontal ligament, and cementum), ultimately resulting in the loss of teeth. The ultimate goal of periodontal therapy is to achieve the regeneration of all of the periodontal tissues. Thus, tissue engineering approaches have been evolving from simple membranes or grafts to more complex constructs. Hydrogels are highly hydrophilic polymeric networks with the ability to simulate the natural microenvironment of cells. In particular, hydrogels offer several advantages when compared to other forms of scaffolds, such as tissue mimicry and sustained drug delivery. Moreover, hydrogels can maintain a moist environment similar to the oral cavity. Hydrogels allow for precise placement and retention of regenerative materials at the defect site, minimizing the potential for off-target effects and ensuring that the treatment is focused on the specific defect site. As a mechanism of action, the sustained release of drugs presented by hydrogels allows for control of the disease by reducing the inflammation and attracting host cells to the defect site. Several therapeutic agents, such as antibiotics, anti-inflammatory and osteogenic drugs, have been loaded into hydrogels, presenting effective benefits in periodontal health and allowing for sustained drug release. This review discusses the causes and consequences of periodontal disease, as well as the advantages and limitations of current treatments applied in clinics. The main components of hydrogels for periodontal regeneration are discussed focusing on their different characteristics, outcomes, and strategies for drug delivery. Novel methods for the fabrication of hydrogels are highlighted, and clinical studies regarding the periodontal applications of hydrogels are reviewed. Finally, limitations in current research are discussed, and potential future directions are proposed.

Exploring the Relationship between Periodontitis, Anti-Periodontitis Therapy, and Extra-Oral Cancer Risk: Findings from a Nationwide Population-Based Study

This study aimed to evaluate the systemic impact of periodontitis, previously considered a local disease, on cancer occurrence. We enrolled 683,854 participants, comparing cancer incidence among those with and without periodontitis and assessing the impact of periodontal treatment on cancer risk. Regardless of gender, age, Charlson comorbidity index, or the use of non-steroidal anti-inflammatory drugs, periodontitis patients had a lower overall cancer risk than controls. However, men with periodontitis had a higher risk of prostate cancer (adjusted hazard ratio [aHR] = 1.22; 95% confidence interval [CI] = 1.10-1.35), and both men and women had a higher risk of thyroid cancer (women: aHR = 1.20, 95%CI = 1.04-1.38; men: aHR = 1.51, 95% CI = 1.15-1.99). Patients with periodontitis who received treatment showed a reduced cancer risk (aHR = 0.41; 95% CI = 0.38-0.44) compared to untreated patients. Proper treatment for periodontitis may lower an individual's cancer risk more than if they did not have the disease at all, suggesting that periodontitis is a modifiable risk factor for cancer.