Isolation and immunohistochemical characterization of periodontal ligament stem cells: A preliminary study

Effects of Stress on Biological Characteristics and Metabolism of Periodontal Ligament Stem Cells of Deciduous Teeth

INTRODUCTION AND AIMS

Periodontal ligament stem cells (PDLSCs) from deciduous teeth (DePDLSCs) can perceive and respond to mechanical signals upon exposure to various environments. The effects of mechanical stress on the biological characteristics and metabolism of DePDLSCs were investigated using in vitro stress loading.

METHODS

DePDLSCs were subjected to mechanical stresses of different strengths. Cell proliferation, expression of osteogenic/osteoclastic factors, apoptosis, and oxidative stress levels were evaluated using CCK-8 assays, alkaline phosphatase staining, real-time PCR, flow cytometry, and malondialdehyde and superoxide dismutase assays. Liquid chromatography-mass spectrometry was used to perform nontargeted metabolomic detection and analysis.

RESULTS

Under stresses of 75 and 150 kPa, the expression of osteogenesis-related factors OPG, ALP, and RUNX2 decreased, and the ratio of RANKL/OPG significantly increased. A pressure of 150 kPa induced oxidative stress and caused a significant increase in cell apoptosis. Among the differential metabolites screened from the 150 kPa group, spermine, spermidine, ceramide, phosphatidylethanolamine, lysophosphatidylethanolamine, linoleic acid, and docosatrienoic acid were the most significantly upregulated. The metabolites screened from the 75 kPa group were mainly related to glycerophospholipid and sphingolipid metabolism, oxidative phosphorylation, and mineral absorption, which were common pathways affected in both experimental groups.

CONCLUSION

A certain degree of mechanical stress can inhibit the proliferative activity and osteogenic differentiation of DePDLSCs, enhance their osteoclast-inducing ability, and cause elevated levels of cell apoptosis and oxidative stress. The metabolic expression profile of DePDLSCs changed significantly under stress. Understanding changes in cellular activity and metabolic reactions may provide an experimental basis for elucidating the role of mechanical stress in root resorption and periodontal tissue remodelling of deciduous teeth.

CLINICAL RELEVANCE

Mechanical stress may affect periodontal tissue remodeling and root resorption of DePDLSc.

Summed Tissue Resistance of Periodontal Ligaments and Alveolar Bone in Orthodontic Distal Retraction of Maxillary Canines: Mathematical Simulation of Clinical Data and Interpretation of Results

Background: The mechanical properties of either alveolar bone or periodontal ligaments under orthodontic loading, as well as orthodontic tooth movement, have been studied in recent years using computational approaches. In previous studies, we developed a theoretical mathematical approach that uses a weighting coefficient of the summed resistance of periodontal structures, namely the bone and periodontal ligaments, in relation to apex movement, the center of rotation, orthodontic force loading, and time in order to quantify the biological response to orthodontic biomechanics. Methods: We analyzed the distal retraction of three maxillary canines and integrated the clinical data obtained in the previously developed mathematical programs. Results: The values of the (σ) weighting coefficient of the tissue resistance were interpreted in the context of the clinical data obtained: the smaller the value of (σ), the higher the actual tissue resistance, with a greater difference between the crown and root movement; also, the higher the value of (σ), the lower the actual tissue resistance, with a small difference between the crown and apex movement. Conclusions: The clinical interpretation of the results allows us to set a premise for the refinement of the mathematical programs so that we can use them in assessing the orthodontic biomechanics of larger patient groups over longer periods of time and create premises of treatment protocol simplification and adjustment.

Gene Polymorphism Influencing Persistent Bone Resorption in Brown Tumor: A Case Series with Possible Pathogenesis and Potential Therapeutic Approach

Brown tumor represents a terminal stage of bone remodeling process due to an imbalance between osteoclastic and osteoblastic activity. It represents a reparative cellular process, rather than a neoplastic process mostly associated with primary or secondary hyperparathyroidism. Although parathyroidectomy is the first treatment of choice for brown tumors, several cases don't resolve even after normalization of parathyroid hormone levels which leads to surgical intervention. Therefore, to avoid multiple bone surgeries in the same patient, it is crucial to have a conservative approach like targeted therapy which could block certain molecules involved in bone resorption. In this string, we have recognized and quantified three molecules namely sclerostin, MCP-1 and CD73 in brown tumors and correlated their expression with bone resorption pathogenesis and potential therapeutic approach.

Adult Mesenchymal Stem Cells from Oral Cavity and Surrounding Areas: Types and Biomedical Applications

Adult mesenchymal stem cells are those obtained from the conformation of dental structures (DMSC), such as deciduous and permanent teeth and other surrounding tissues. Background: The self-renewal and differentiation capacities of these adult stem cells allow for great clinical potential. Because DMSC are cells of ectomesenchymal origin, they reveal a high capacity for complete regeneration of dental pulp, periodontal tissue, and other biomedical applications; their differentiation into other types of cells promotes repair in muscle tissue, cardiac, pancreatic, nervous, bone, cartilage, skin, and corneal tissues, among others, with a high predictability of success. Therefore, stem and progenitor cells, with their exosomes of dental origin and surrounding areas in the oral cavity due to their plasticity, are considered a fundamental pillar in medicine and regenerative dentistry. Tissue engineering (MSCs, scaffolds, and bioactive molecules) sustains and induces its multipotent and immunomodulatory effects. It is of vital importance to guarantee the safety and efficacy of the procedures designed for patients, and for this purpose, more clinical trials are needed to increase the efficacy of several pathologies. Conclusion: From a bioethical and transcendental anthropological point of view, the human person as a unique being facilitates better clinical and personalized therapy, given the higher prevalence of dental and chronic systemic diseases.

Bioinductive and anti-inflammatory properties of Propolis and Biodentine on SHED

Objectives

This study aimed to evaluate and compare the cell viability, differentiation potential and anti-inflammatory potential of propolis and Biodentine™ on stem cells isolated from human exfoliated deciduous teeth (SHED).

Materials and methods

SHED were segregated and cultured from the dental pulp of children after therapeutic extraction. Microculture Tetrazolium Assay (MTT) assay was carried out for assessing cell proliferation potential of propolis and Biodentine at different concentrations. As per the results from cell proliferation assay, cell differentiation potential of SHED was evaluated at concentration of 12.5 μg/ml using Alizarin Red staining. The anti-inflammatory potential of test materials was evaluated using gelatin zymography by detecting MMP-2 and MMP-9.

Results

The maximum cell proliferation percentage of SHED treated with propolis and Biodentine was observed at a concentration of 12.5 μg/ml, on day 7, 14 and 21 with Biodentine having maximum cell proliferation potential followed by propolis. SHED treated with Biodentine showed maximum cell differentiation on day 7 (107.16), 14 (106.29) and 21 (107.72). However, anti-inflammatory activity against MMP-2 was 95 % with propolis and 85 % with Biodentine and whereas, against MMP-9 it was 65 % for propolis and 47 % for Biodentine.

Conclusion

Propolis shows comparable cell viability, cell proliferation and differentiation potential on SHED when compared to Biodentine. It also exhibits better invitro anti-inflammatory activity on SHED compared to Biodentine. Further studies are warranted to validate the application of propolis as an effective and economical alternative biocompatible agent to Biodentine for vital pulp therapies.