Proliferative effect of cannabidiol in human gingival fibroblasts via the mitogen-activated extracellular signal-regulated kinase (MEK) 1/2

Enhanced osteogenic differentiation of human periodontal ligament cells by mature osteoclasts

OBJECTIVE

Several in vitro studies have shown that reverse signaling from osteoclasts regulates osteoblast differentiation and mineralization. However, none of these studies have reported the effects of this signaling pathway on periodontal ligament (PDL) cells. Therefore, in this study, we aimed to investigate the interaction between receptor activators of nuclear factor kappa B (RANK) released from mature human osteoclasts and the membranous RANK ligand (RANKL) in human PDL cells.

METHODS

Multinucleated mature human osteoclasts were differentiated from peripheral blood mononuclear cells upon incubation with recombinant macrophage colony-stimulating factor and RANKL. Mature osteoclasts and human PDL cells were characterized. A mature osteoclast-conditioned medium (OC-CM) was used to induce osteogenic differentiation of PDL cells. Mechanistic analysis of RANK-RANKL reverse signaling were conducted to determine the regulation of osteogenic induction using conditioned medium from mature osteoclasts treated with GW4869 (GW-OC-CM) or PDL cells pretreated with recombinant human osteoprotegerin (OPG).

RESULTS

OC-CM significantly upregulated the mRNA expression of osteogenic genes and enhanced the osteogenic differentiation and biomineralization of PDL cells (p < 0.05). GW-OC-CM significantly reduced the expression of osteogenic genes, osteogenic differentiation, and biomineralization in PDL cells (p < 0.05). Similarly, the pretreatment of PDL cells with OPG before OC-CM treatment significantly reduced the osteogenic induction of PDL cells (p < 0.05).

CONCLUSION

Mature osteoclasts can induce osteogenesis in human PDL cells via RANK-RANKL reverse signaling.

Investigating the interplay between environmental conditioning and nanotopographical cueing on the response of human MG63 osteoblastic cells to titanium nanotubes

Titanium nanotubular surfaces have been extensively studied for their potential use in biomedical implants due to their ability to promote relevant phenomena associated with osseointegration, among other functions. However, despite the large body of literature on the subject, potential synergistic/antagonistic effects resulting from the combined influence of environmental variables and nanotopographical cues remain poorly investigated. Specifically, it is still unclear whether the nanotube-induced variations in cellular activity are preserved across different biochemical contexts. To bridge this gap, this study systematically evaluates the combined influence of nanotopographical cues and environmental factors on human MG63 osteoblastic cells. To this end, we capitalized on a triphasic anodization protocol to create nanostructured surfaces characterized by an average nanotube inner diameter of 25 nm (NT1) and 82 nm (NT2), as well as a two-tiered honeycomb (HC) architecture. A variable glucose content was chosen as the environmental modifier due to its well-known ability to affect specific functions of MG63 cells. Alkaline phosphatase (ALP), viability/metabolic activity and proliferation were quantified to identify the suitable preconditioning window required for dictating a change in behaviour without significantly damaging cells. Successively, a combination of immunofluorescence, colorimetric assays, live cell imaging and western blots quantified viability/metabolic activity and cell proliferation, migration and differentiation as a function of the combined effects exerted by the nanostructured substrates and the glucose content. To achieve a thorough understanding of MG63 cell adaptation and response, a comparative analysis table that includes and systematically cross-analyzes all variables from this study was used for interpretation and discussion of the results. Taken together, we have demonstrated that all surfaces mitigate the negative effects of high glucose. However, nanotubular topographies, particularly NT2, elicit a more beneficial outcome in high glucose in respect to untreated titanium. In addition, while NT1 surfaces are associated with the most stable cellular response across varying glucose levels, the NT2 and HC substrates exhibit the strongest enhancement of cell migration, viability/metabolism and differentiation. Moreover, shorter-term processes such as adhesion and proliferation are favored on untreated titanium, while anodized samples support later-term events. Lastly, the role of anodized surfaces is dominant over the effects of environmental glucose, underscoring the importance of carefully considering nanoscale surface features in the design and development of cell-instructive titanium surfaces.

Overexpression of inflammatory human caspase-4 in relation to clinical severity of oral lichen planus

OBJECTIVE

Involvement of non-canonical inflammasome, comprising inflammatory human caspase-4, caspase-5, and Gasdermin D, in the pathogenesis of oral lichen planus (OLP) has never been demonstrated. We aimed to determine human caspase-4, caspase-5, and Gasdermin D expressions in OLP, to correlate their expressions with OLP severity, and to measure salivary interleukin (IL)-1β levels.

STUDY DESIGN

OLP and normal oral mucosal specimens (n = 42 each) were processed for immunohistochemistry or immunoblotting. The clinical score for OLP severity was assessed at the most severe site. The immunohistochemical (IHC) score was a summation of intensity and positive cell scores. Salivary IL-1β levels were measured by enzyme-linked immunosorbent assay (ELISA).

RESULTS

Median IHC scores of caspase-4 and Gasdermin D in OLP group were significantly greater than those in normal mucosal group (P < .01), consistent with significantly upregulated expressions by immunoblotting (P < .05). The IHC scores of caspase-4 and Gasdermin D were positively correlated with the clinical scores (P < .05). Salivary IL-1β levels in the OLP group were significantly greater than those in the normal mucosal group (P < .001).

CONCLUSIONS

Our study demonstrates enhanced human caspase-4 and Gasdermin D expressions in relation to increased OLP severity with elevated salivary IL-1β levels, proposing clinical applications of these biomolecules as potential prognostic markers and/or new therapeutic intervention for OLP.

Phytocannabinoids and gingival inflammation: Preclinical findings and a placebo-controlled double-blind randomized clinical trial with cannabidiol

OBJECTIVE

The aim of this study was to: (1) evaluate the anti-inflammatory effects of cannabidiol (CBD) on primary cultures of human gingival fibroblasts (HGFs) and (2) to clinically monitor the effect of CBD in subjects with periodontitis.

BACKGROUND

The use of phytocannabinoids is a new approach in the treatment of widely prevalent periodontal disease.

MATERIALS AND METHODS

Cannabinoid receptors were analyzed by western blot and interleukin production detected using enzyme immunoassay. Activation of the Nrf2 pathway was studied via monitoring the mRNA level of heme oxygenase-1. Antimicrobial effects were determined by standard microdilution and 16S rRNA screening. In the clinical part, a placebo-control double-blind randomized study was conducted (56 days) in three groups (n = 90) using dental gel without CBD (group A) and with 1% (w/w) CBD (group B) and corresponding toothpaste (group A - no CBD, group B - with CBD) for home use to maintain oral health. Group C used dental gel containing 1% chlorhexidine digluconate (active comparator) and toothpaste without CBD.

RESULTS

Human gingival fibroblasts were confirmed to express the cannabinoid receptor CB2. Lipopolysaccharide-induced cells exhibited increased production of pro-inflammatory IL-6 and IL-8, with deceasing levels upon exposure to CBD. CBD also exhibited antimicrobial activities against Porphyromonas gingivalis, with an MIC of 1.5 μg/mL. Activation of the Nrf2 pathway was also demonstrated. In the clinical part, statistically significant improvement was found for the gingival, gingival bleeding, and modified gingival indices between placebo group A and CBD group B after 56 days.

CONCLUSIONS

Cannabidiol reduced inflammation and the growth of selected periodontal pathogenic bacteria. The clinical trial demonstrated a statistically significant improvement after CBD application. No adverse effects of CBD were reported by patients or observed upon clinical examination during the study. The results are a promising basis for a more comprehensive investigation of the application of non-psychotropic cannabinoids in dentistry.

Cannabinoids in Periodontology: Where Are We Now?

INTRODUCTION

Cannabinoids are a well-documented treatment modality for various immune and inflammatory diseases, including asthma, chronic obstructive pulmonary disease, Crohn's disease, arthritis, multiple sclerosis, and a range of neurodegenerative conditions. However, limited information is available regarding the therapeutic potential of cannabinoids in treating periodontal disease.

OBJECTIVE

The objective of this study is to analyze the current evidence on the antibacterial and immunomodulatory effects of cannabis and its role in the healing and regeneration processes within periodontal tissues.

RESULTS

This review discusses the potential role of cannabinoids in restoring periodontal tissue homeostasis.

CONCLUSIONS

The examination of the endocannabinoid system and the physiological effects of cannabinoids in the periodontium suggests that they possess immunomodulatory and antibacterial properties, which could potentially promote proper tissue healing and regeneration.