Inhomogeneity of stiffness and density of the extracellular matrix within the leukoplakia of human oral mucosa as potential physicochemical factors leading to carcinogenesis.

Oral leukoplakia is a clinical term relating to various morphological lesions, including squamous cell hyperplasia, dysplasia and carcinoma. Leukoplakia morphologically manifested as hyperplasia with epithelial dysplasia is clinically treated as precancerous condition. Nevertheless, there is a lack of good markers indicating the transformation of premalignancies towards cancer. A better understanding of the mechanical environment within the tissues where tumors grow might be beneficial for the development of prevention, diagnostic, and treatment methods in cancer management. Atomic force microscopy (AFM) and immunohistology techniques were used to assess changes in the stiffness and morphology of oral mucosa and leukoplakia samples at different stages of their progression towards cancer. The Young's moduli of the tested leukoplakia samples were significantly higher than those of the surrounding mucus. Robust inhomogeneity of stiffness within leukoplakia samples, reflecting an increase in regeneration and collagen accumulation (increasing density) in the extracellular matrix (ECM), was observed. Within the histologically confirmed cancer samples, Young's moduli were significantly lower than those within the precancerous ones. Inhomogeneous stiffness within leukoplakia might act as "a mechanoagonist" that promotes oncogenesis. In contrast, cancer growth might require the reorganization of tissue structure to create a microenvironment with lower and homogenous stiffness. The immunohistology data collected here indicates that changes in tissue stiffness are achieved by increasing cell/ECM density. The recognition of new markers of premalignancy will aid in the development of new therapies and will expand the diagnostic methods.

Bacteria Residing at Root Canals Can Induce Cell Proliferation and Alter the Mechanical Properties of Gingival and Cancer Cells.

Understanding the importance of oral microbiota in human health and disease also leads to an expansion of the knowledge on functional, metabolic, and molecular alterations directly contributing to oral and systemic pathologies. To date, a compelling number of studies have documented the crucial role of some oral cavity-occurring microbes in the initiation and progression of cancers. Although this effect was noted primarily for Fusobacterium spp., the potential impact of other oral microbes is also worthy of investigation. In this study, we aimed to assess the effect of Enterococcus faecalis, Actinomyces odontolyticus, and Propionibacterium acnes on the proliferation capability and mechanical features of gingival cells and cell lines derived from lung, breast, and ovarian cancers. For this purpose, we incubated selected cell lines with heat-inactivated bacteria and supernatants collected from biofilms, cultured in both anaerobic and aerobic conditions, in the presence of surgically removed teeth and human saliva. The effect of oral bacteria on cell population growth is variable, with the highest growth-promoting abilities observed for E. faecalis in relation to human primary gingival fibroblasts (HGF) and lung cancer A549 cells, and P. acnes in relation to breast cancer MCF-7 and ovarian cancer SKOV-3 cells. Notably, this effect seems to depend on a delicate balance between the pro-stimulatory and toxic effects of bacterial-derived products. Regardless of the diverse effect of bacterial products on cellular proliferation capability, we observed significant alterations in stiffness of gingival and lung cancer cells stimulated with E. faecalis bacteria and corresponding biofilm supernatants, suggesting a novel molecular mechanism involved in the pathogenesis of diseases in oral cavities and tooth tissues. Accordingly, it is proposed that analysis of cancerogenic features of oral cavity bacteria should be multivariable and should include investigation of potential alterations in cell mechanical properties. These findings corroborate the important role of oral hygiene and root canal treatment to assure the healthy stage of oral microbiota.

Artificial Saliva: Challenges and Future Perspectives for the Treatment of Xerostomia.

The chronic sensation of a dry mouth is a disease condition called xerostomia and affects a large part of the population. Xerostomia is associated with decreased secretion, or more often, qualitative changes in saliva proteins and immunoglobulin concentrations that develop as a result of salivary gland dysfunction. Several reasons causing dry mouth were described, and usually, they include taking medications, diseases or radiotherapy. In some situations, when it is difficult to use salivary stimulants or salivary gland damage is irreversible, the only option might seem to be saliva substitutes. The paper presents the most important aspects considering saliva preparations. The rheological and lubricating properties and the reconstruction of the complex saliva structure has been the main purpose of research. The biological properties of saliva preparations were also widely discussed. As part of the work, the antimicrobial effect of three commercial saliva preparations was tested. Finally, inadequate antimicrobial properties against the strains isolated from the oral cavity were demonstrated. The development of salivary substitutes, in particular, the improvement of antimicrobial properties, can be achieved using nanotechnology, including drug delivery systems containing nanocarriers.

Beneficial Effects of Vitamins K and D3 on Redox Balance of Human Osteoblasts Cultured with Hydroxyapatite-Based Biomaterials.

Hydroxyapatite-based biomaterials are commonly used in surgery to repair bone damage. However, the introduction of biomaterials into the body can cause metabolic alterations, including redox imbalance. Because vitamins D3 and K (K1, MK-4, MK-7) have pronounced osteoinductive, anti-inflammatory, and antioxidant properties, it is suggested that they may reduce the adverse effects of biomaterials. The aim of this study was to investigate the effects of vitamins D3 and K, used alone and in combination, on the redox metabolism of human osteoblasts (hFOB 1.19 cell line) cultured in the presence of hydroxyapatite-based biomaterials (Maxgraft, Cerabone, Apatos, and Gen-Os). Culturing of the osteoblasts in the presence of hydroxyapatite-based biomaterials resulted in oxidative stress manifested by increased production of reactive oxygen species and decrease of glutathione level and glutathione peroxidase activity. Such redox imbalance leads to lipid peroxidation manifested by an increase of 4-hydroxynonenal level, which is known to influence the growth of bone cells. Vitamins D3 and K were shown to help maintain redox balance and prevent lipid peroxidation in osteoblasts cultured with hydroxyapatite-based biomaterials. The strongest effect was observed for the combination of vitamin D3 and MK-7. Moreover, vitamins promoted growth of the osteoblasts, manifested by increased DNA biosynthesis. Therefore, it is suggested that the use of vitamins D3 and K may protect redox balance and support the growth of osteoblasts affected by hydroxyapatite-based biomaterials.

The Role of Oral Cavity Biofilm on Metallic Biomaterial Surface Destruction-Corrosion and Friction Aspects.

Metallic biomaterials in the oral cavity are exposed to many factors such as saliva, bacterial microflora, food, temperature fluctuations, and mechanical forces. Extreme conditions present in the oral cavity affect biomaterial exploitation and significantly reduce its biofunctionality, limiting the time of exploitation stability. We mainly refer to friction, corrosion, and biocorrosion processes. Saliva plays an important role and is responsible for lubrication and biofilm formation as a transporter of nutrients for microorganisms. The presence of metallic elements in the oral cavity may lead to the formation of electro-galvanic cells and, as a result, may induce corrosion. Transitional microorganisms such as sulfate-reducing bacteria may also be present among the metabolic microflora in the oral cavity, which can induce biological corrosion. Microorganisms that form a biofilm locally change the conditions on the surface of biomaterials and contribute to the intensification of the biocorrosion processes. These processes may enhance allergy to metals, inflammation, or cancer development. On the other hand, the presence of saliva and biofilm may significantly reduce friction and wear on enamel as well as on biomaterials. This work summarizes data on the influence of saliva and oral biofilms on the destruction of metallic biomaterials.

Histone deacetylases affect transcriptional regulation of CCL2 and CXCL8 expression by pulmonary fibroblasts in vitro.

INTRODUCTION: Chemokines have been shown to play an important role in tissue remodeling and fibrosis in the respiratory system. In this study we wanted to evaluate the mechanisms, which regulate the expression of selected chemokines by pulmonary fibroblasts in vitro. MATERIAL AND METHODS: Pulmonary fibroblasts were cultured with and without bacterial lipopolysaccharide (LPS) for 6 hours. In addition some of the cultures were pre-treated with histone deacetylase inhibitor Trichostatin A (TSA). Real-time PCR reaction was performed to estimate the expression of chemokines CCL2, CCL3 and CXCL8. RESULTS: In unstimulated cultures detectable expression of CCL2 and CXCL8 was observed, while CCL3 expression could not be detected. After stimulation with LPS, TSA and both agents together CCL2 expression rose by 1.52, 1.62 and 1.8 times in comparison to control cultures respectively. CXCL8 mRNA expression levels after stimulation with LPS, TSA and LPSTSA increased by 1.53, 1.91 and 2.4 times accordingly. CONCLUSION: Epigenetic mechanisms related to histone acetylation affects transcriptional regulation of CCL2 and CXCL8 expression by pulmonary fibroblasts. Those mechanisms may play a role in tissue repair and pathologic remodeling.

Clinical evaluation of photodynamic therapy efficacy in the treatment of oral leukoplakia.

BACKGROUND: The aim of the study was clinical evaluation of photodynamic therapy efficacy in the treatment of oral leukoplakia lesions. METHODS: Twenty-three consecutive patients aged 21-79 were included to the study. In all patients 44 homogeneous, flat leukoplakia lesions were clinically diagnosed and confirmed histopathologically. Photodynamic therapy was performed with the use of Photolon(®) photosensitizer, containing 20% Chlorine-e6 and 10% dimethyl sulfoxide and a semiconductor laser, with power up to 300mW and a wavelength of 660nm. Ten illumination sessions were conducted with the use of superficial light energy density of 90J/cm(2). RESULTS: At baseline the mean size of leukoplakia lesion was 6.5±5.10cm(2) while after photodynamic therapy 3±2.99cm(2). Significant reduction (on average by 53.8%) of leukoplakia lesions sizes was observed after therapy. Twelve (27.27%) lesions had been completely cured, 22 (50%) partially cured, although 10 (22.73%) lasted unchanged. The efficacy of PTD was comparable in women and men irrespective of age. There have been no adverse site effects during therapy noted. CONCLUSIONS: Within the limits of the study it can be concluded that photodynamic therapy with the use of Chlorine-e6 can lead to considerable reduction of oral leukoplakia lesions size thus may be useful in clinical practice. However there is a need of further studies on larger number of cases and longer follow-up time.

Cytological picture of the oral mucosa in patients with gastric and colon cancer.

The incidence of malignant gastrointestinal cancers in Poland has been constantly growing, which has led to an intensification of the search for new markers of the early clinical stage of this disease. The oral cavity,as the first part of the gastrointestinal tract, has a very important role. The oral cavity presents symptoms of both typically stomatological and systemic diseases. Oral cancers, benign or malignant, may originate and grow in any of the tissues of the mouth, and within this small area they may be of varied clinical, histological and biological features. These can be lesions typically observed in the oral cavity, but also characteristic of cases where the symptoms occur both in the mouth and in other body parts. The aim of this study was to present a cytological picture of the oral mucosa in patients with gastric and colon cancer and to compare the cytological picture with that obtained from a group of patients with no cancer, using the Papanicolaou classification and the Bethesda system. The study was conducted in 126 patients treated surgically in the II General and Gastroenterological Surgery Clinic between 2006 and 2008. All patients were divided into two groups based on the type of lesions. In both of the studied groups, more than half of the patients did not present any abnormalities in the mucosa of the mouth, lips and cheeks in the physical examination. None of the patients had erosion, ulceration or lesions typical of leukoplakia or lichen planus. No malignant cells were detected in either of the studied groups, and there were no well-defined lesions found in the oral cavity that would distinguish the patients with gastrointestinal cancer.