Epithelial cells from oral mucosa: How to cultivate them?

Exfoliated oral mucosa cells as bioindicators of short- and long-term systemic titanium contamination

BACKGROUND

Humans are exposed to exogenous sources of titanium-containing particles that can enter the body mainly by inhalation, ingestion, or dermal absorption. Given the widespread use of biomaterials in medicine, the surface of a titanium (Ti) biomedical device is a potential endogenous source of Ti ions and/or Ti-containing particles, such as TiO₂ micro-(MPs) and nano-particles (NPs), resulting from biotribocorrosion processes. Ti ions or Ti-containing particles may deposit in epithelial cells of the oral mucosa, and the latter may therefore serve as bioindicators of short and long-term systemic Ti contamination. The aim of the present study was to histologically and quantitatively evaluate the presence of Ti traces in cells exfoliated from the oral mucosa as possible bioindicators of systemic contamination with this metal at short and long-term experimental time points METHODS: Thirty Wistar rats were intraperitoneally injected with a suspension of titanium dioxide (TiO₂) (0.16 g/100 g body weight of TiO₂ in 5 ml of NaCl 0.9%) using 5 nm NPs (Group: TiO₂-NP5; n = 10), 45 µm MPs (Group: TiO₂-MP45; n = 10), or vehicle alone (Control group; n = 10). At one and six months post-injection, right-cheek mucosa cells were obtained by exfoliative cytology using a cytobrush; they were spray fixed and stained using Safranin or the Papanicolaou technique. The smears were cytologically evaluated (light microscopy) to determine the presence of particulate material, which was also analyzed microchemically (SEM-EDS). Left-cheek mucosa cells were similarly obtained and re-suspended in 5 ml of PBS (pH: 7.2-7.4); the samples corresponding to each group were pooled together and analyzed spectrometrically (ICP-MS) to determine Ti concentration in each of the studied groups. Blood samples were obtained for histological determination of the presence of particulate material on Safranin-stained blood smears and determination of plasma concentration of Ti by ICP-MS RESULTS: Different size and shape metal-like particles were observed inside and outside epithelial cells in TiO₂-NP5 and TiO₂-MP45 cytological smears at both one and six months post-injection. EDS analysis showed the presence of Ti in the particles. ICP-MS revealed higher Ti concentrations in both TiO₂ injected groups compared to the control group. In addition, Ti concentration did not vary with time or particle size. Monocytes containing particles were observed in blood smears of TiO₂-exposed animals one- and six-months post-injection. Plasma levels of Ti were significantly higher in TiO₂-NP5- and TiO₂-MP45- exposed animals than in controls (p < 0.05), and Ti concentration was significantly higher at one month than at six months in both TiO₂-exposed groups (p < 0.05).

CONCLUSIONS

Cells exfoliated from the oral mucosa could be used as bioindicators of short- and long-term systemic contamination with Ti. Exfoliative cytology could be used as a simple, non-invasive, and inexpensive diagnostic method for monitoring biotribocorrosion of Ti implants and patient clinical follow-up.

Modulation of ocular surface desiccation in a murine model by histatin-5 application

PURPOSE

To determine the efficacy of Histatin-5 (Hst5) peptide treatment in ameliorating dry eye disease (DED) phenotype in an in-vivo mouse model of scopolamine and desiccating stress (SDS) dry eye.

METHODS

SDS was induced in female C57BL/6 mice by subcutaneous injections of scopolamine hydrobromide and exposure to low relative humidity and forced air draft for five days. Mouse eyes were topically treated with synthetic Hst5 peptide or balanced salt solution (BSS) twice a day for four days. Control mice were not exposed to SDS induction and did not receive any treatments. Oregon green dextran (OGD) staining was used to evaluate corneal permeability. Histologically, staining with periodic acid schiff (PAS), immunohistochemistry (IHC) and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL), were used to quantify the number of goblet cells (GC), CD45+ immune cells and apoptotic cells respectively in formalin fixed paraffin embedded (FFPE) mouse whole eye sections.

RESULTS

Compared to treatment with BSS, Hst5 treatment significantly lowered corneal epithelial permeability, prevented conjunctival epithelial GC loss, decreased conjunctival CD45+ immune cell infiltration and reduced conjunctival epithelial cell apoptosis.

CONCLUSIONS

Hst5 peptide topical treatment significantly improves the clinical parameters observed in SDS experimental model of DED. This is the first report of the efficacy of Hst5 treatment of dry eye phenotype, and potential novel treatment for DED in the clinic. Hst5 represents a new class of efficacious therapeutic agents, demonstrating pro-epithelial and anti-inflammatory activities at the ocular surface.

Design and synthesis of multifunctional microtubule targeting agents endowed with dual pro-apoptotic and anti-autophagic efficacy

Autophagy is a lysosome dependent cell survival mechanism and is central to the maintenance of organismal homeostasis in both physiological and pathological situations. Targeting autophagy in cancer therapy attracted considerable attention in the past as stress-induced autophagy has been demonstrated to contribute to both drug resistance and malignant progression and recently interest in this area has re-emerged. Unlocking the therapeutic potential of autophagy modulation could be a valuable strategy for designing innovative tools for cancer treatment. Microtubule-targeting agents (MTAs) are some of the most successful anti-cancer drugs used in the clinic to date. Scaling up our efforts to develop new anti-cancer agents, we rationally designed multifunctional agents 5a-l with improved potency and safety that combine tubulin depolymerising efficacy with autophagic flux inhibitory activity. Through a combination of computational, biological, biochemical, pharmacokinetic-safety, metabolic studies and SAR analyses we identified the hits 5i,k. These MTAs were characterised as potent pro-apoptotic agents and also demonstrated autophagy inhibition efficacy. To measure their efficacy at inhibiting autophagy, we investigated their effects on basal and starvation-mediated autophagic flux by quantifying the expression of LC3II/LC3I and p62 proteins in oral squamous cell carcinoma and human leukaemia through western blotting and by immunofluorescence study of LC3 and LAMP1 in a cervical carcinoma cell line. Analogues 5i and 5k, endowed with pro-apoptotic activity on a range of hematological cancer cells (including ex-vivo chronic lymphocytic leukaemia (CLL) cells) and several solid tumor cell lines, also behaved as late-stage autophagy inhibitors by impairing autophagosome-lysosome fusion.

Cytotoxic effects of different detergent containing children's toothpastes on human gingival epithelial cells

Background

This study aimed to evaluate possible cytotoxic effects to gingival epithelial cells exposed to children toothpastes containing different detergent.

Methods

Tissues required for the isolation of human gingival epithelial cells were obtained by biopsy during the extraction of the impacted third molar tooth. Toothpaste solutions of different concentrations were prepared from five different children’s toothpastes with different detergent contents. Isolated gingival epithelial cells were stimulated with experimental groups consisting of toothpaste solutions (Colgate, Sensodyne, Splat, Nenedent, Perlodent) at different concentrations and a control group consisting of complete Dulbecco’s modified eagle medium. After the experiments, cell viability was evaluated using flow cytometry. 2 Way ANOVA was used to see the interaction effect of the main effects of toothpaste solution and concentration factors. Pairwise comparisons were made by Tukey post hoc tests. In the study, the significance level was taken as 0.05.

Results

As a result of the analysis, it was seen that the toothpaste solution and concentration factors and the interactions of these 2 factors were effective on the viable, early apoptotic, late apoptotic and necrotic cell rates. The statistically highest live cell ratios were detected in Splat’s toothpaste solutions (90.14% at 0.4% concentration) after the control group (90.82%) and the group with the lowest viability values was determined in Colgate group (75.74% at 0.4% concentration) (p < 0.05).

Conclusions

According to the results of the study, it was observed that toothpastes containing SLS affected the viability of cells more negatively than toothpastes with other detergent contents.

Progress in Drug and Formulation Development for the Chemoprevention of Oral Squamous Cell Carcinoma: A Review

BACKGROUND

Cancer is a life-threatening global problem with high incidence rates. Prioritizing the prevention of cancer, chemopreventive agents have drawn much attention from the researchers.

OBJECTIVE

This review focuses on the discussion of the progress in the development of chemopreventive agents and formulations related to the prevention of oral cancer.

METHODS

In this perspective, an extensive literature survey was carried out to understand the mechanism, control and chemoprevention of oral cancer. Different patented agents and formulations have also exhibited cancer preventive efficacy in experimental studies. This review summarizes the etiology of oral cancer and developments in prevention strategies.

RESULTS

The growth of oral cancer is a multistep activity necessitating the accumulation of genetic as well as epigenetic alterations in key regulatory genes. Many risk factors are associated with oral cancer. Genomic technique for sequencing all tumor specimens has been made available to help detect mutations. The recent development of molecular pathway and genetic tools has made the process of diagnosis easier, better forecast and efficient therapeutic management. Different chemical agents have been studied for their efficacy to prevent oral cancer and some of them have shown promising results.

CONCLUSION

Use of chemopreventive agents, either synthetic or natural origin, to prevent carcinogenesis is a worthy concept in the management of cancers. Preventive measures are helpful in controlling the occurrence or severity of the disease. The demonstrated results of preventive agents have opened an arena for the development of promising chemopreventive agents in the management of oral squamous cell carcinoma.

Novel zafirlukast derivatives exhibit selective antibacterial activity against Porphyromonas gingivalis

Periodontal disease is an oral chronic immune-inflammatory disease highly prevalent worldwide that is initiated by specific oral bacterial species leading to local and systemic effects. The development of new preventive/therapeutic strategies to specifically target oral periodontopathogens without perturbing oral microbiome species normally colonizing the oral cavity is needed. The fast and affordable strategy of repositioning of already FDA-approved drugs can be an answer to the development of novel treatments against periodontal pathogens such as Porphyromonas gingivalis. Herein, we report the synthesis and antibacterial activity of novel zafirlukast derivatives, their bactericidal effect, and their cytotoxicity against oral epithelial cell lines. Many of these derivatives exhibited superior antibacterial activity against P. gingivalis compared to the parent drug zafirlukast. The most promising compounds were found to be selective against P. gingivalis and they were bactericidal in their activity. Finally, we demonstrated that these potent derivatives of zafirlukast provided a better safety profile against oral epithelial cells compared to zafirlukast.