Areca nut extracts modulated expression of alkaline phosphatase and receptor activator of nuclear factor kappaB ligand in osteoblasts

Betel Nut Chewing Decreased Calcaneus Ultrasound T-Score in a Large Taiwanese Population Follow-Up Study

Chewing betel nut is common in Taiwan. Although previous studies have shown that chewing betel nuts is associated with adverse health effects, findings about the impact on bone density have been inconsistent. Therefore, the aim of this study was to investigate the correlation between betel nut chewing and calcaneus ultrasound T-score in a longitudinal study of 118,856 participants from the Taiwan Biobank. Of these participants, 27,002 were followed up with for a median of 4 years. The T-score of the calcaneus was measured in the non-dominant foot using ultrasound. Multivariable analysis showed that a history of chewing betel nut (coefficient β = -0.232; p < 0.001) was significantly associated with low baseline T-score in all participants (n = 118,856). In addition, a long duration of betel nut chewing (per 1 year; coefficient β = -0.003; p = 0.022) was significantly associated with a low baseline T-score in the participants with a history of chewing betel nut (n = 7210). Further, a long duration of betel nut chewing (per 1 year; coefficient β = -0.004; p = 0.039) was significantly associated with a low ΔT-score in the participants with a history of chewing betel nut (n = 1778) after 4 years of follow-up. In conclusion, our results showed that betel nut chewing was associated with a decrease in calcaneus ultrasound T-score, and thus, it is important to stop chewing betel nut to help prevent an increased risk of osteoporosis in the Taiwanese population.

Modulation of proinflammatory mediators by viruses-bacteria synergism in human osteoblasts-an in vitro study

BACKGROUND/PURPOSE

Viruses-bacteria synergistic interaction is associated with destructive periodontal diseases. However, the underlying mechanism for tissue destruction is not fully elucidated. In this study, lipopolysaccharide from Porphyromonas gingivalis (Pg-LPS) and polyinosinic-polycytidylic acid (poly I:C) were used to simulate bacteria and viruses, respectively. The possible combined effects of both molecular patterns on secretion of interleukin (IL)-6 and prostaglandin E₂ (PGE₂) from osteoblasts were determined. The effects of povidone-iodine (PVP-I) on the secretion of IL-6 and PGE₂ were also examined.

METHODS

Viability of treated osteoblastic cells (MG63) was examined by detection the mitochondrial dehydrogenase activity. Secretion of IL-6 and PGE₂ was detected using the enzyme-linked immunosorbent assay (ELISA). Mitogen-activated protein kinases (MAPKs) and cyclooxygenase-2 (COX-2) were determined using the Western blotting analysis.

RESULTS

Pg-LPS or poly I:C significantly enhanced the production of IL-6 and PGE₂ in MG63 cells. The additive/synergistic effects of Pg-LPS/poly I:C on production of IL-6 and PGE₂ were evident. The levels of phosphorylation of p38 MAPK and c-Jun N-terminal kinase (JNK) and expression of COX-2 protein were enhanced by Pg-LPS and/or poly I:C. On the other hand, the level of phosphorylation of extracellular signal-regulated kinase (ERK) was reduced by Pg-LPS and/or poly I:C. The stimulatory secretion of PGE₂ by poly I:C was significantly reduced by PVP-I.

CONCLUSION

Concomitant infection of viruses and bacteria may be potentially harmful to the tooth supporting tissues by production of proinflammatory mediators. The results suggest the potential anti-inflammatory effect of PVP-I on bacterial or viral infection.

An epidemiological study to assess periodontal status among sugar factory workers of Karad taluka using community periodontal index

Objectives:

Oral health is an integral component of general health. Periodontal disease is one of the most prevalent dental diseases among the population. Researchers have identified an association of various risk factors with periodontal disease. The study aimed to assess the periodontal status among the sugar factory workers of Karad taluka.

Materials and Methods:

The study was conducted among 1200 subjects in the age group of 25-54 years. Personal and sociodemographic data were recorded in the proforma based on the WHO oral health survey form (1997). Periodontal status was assessed using community periodontal index (CPI). For statistical analyses, Chi-square test and Multiple Logistic Regression analyses was performed.

Results:

The sociodemographic characteristics (age, sex, and socioeconomic status) and deleterious habits like tobacco chewing and smoking were found to be significantly associated with the CPI and LoA scores for the population (P < 0.00001).

Conclusion:

The analysis of the results obtained in this epidemiological study evidenced that periodontitis is prevalent among the sugar factory workers of Karad taluka. There is a need for emphasis on the preventive care.

Relationship between betel quid chewing and radiographic alveolar bone loss among Taiwanese aboriginals: a retrospective study

Background

Betel quid chewing is associated with the periodontal status; however, results of epidemiological studies are inconsistent. To the best of our knowledge, no study has reported radiographic alveolar bone loss (RABL) associated with betel quid chewing.

Methods

This survey was conducted in an aboriginal community in Taiwan because almost all betel quid chewers were city-dwelling cigarette smokers. In total, 114 subjects, aged 30–60 years, were included. Full-mouth intraoral RABL was retrospectively measured and adjusted for age, gender, and plaque index (PI). Multiple regression analysis was used to assess the relationship between RABL and potential risk factors.

Results

Age-, gender-, and PI-adjusted mean RABL was significantly higher in chewers with or without cigarette smoking than in controls. Multiple regression analysis showed that the RABL for consumption of 100,000 pieces betel quid for the chewer group was 0.40 mm. Full-mouth plotted curves for adjusted mean RABL in the maxilla were similar between the chewer and control groups, suggesting that chemical effects were not the main factors affecting the association between betel quid chewing and the periodontal status.

Conclusion

Betel quid chewing significantly increases RABL. The main contributory factors are age and oral hygiene; however, the major mechanism underlying this process may not be a chemical mechanism. Regular dental visits, maintenance of good oral hygiene, and reduction in the consumption of betel quid, additives, and cigarettes are highly recommended to improve the periodontal status.

Inhibitory effects of areca nut extract on expression of complement receptors and fc receptors in human neutrophils

BACKGROUND

Chewing of areca quid increases the prevalence of periodontal diseases. Areca nut extract (ANE) inhibits the phagocytic activity of human neutrophils. This in vitro study investigates the effects of ANE on complement- and antibody-opsonized phagocytosis by neutrophils. Expression of complement receptors, Fc receptors, and F-actin in ANE-treated neutrophils is also analyzed.

METHODS

The viability of ANE-treated neutrophils was determined using the propidium iodide staining method. The possible effects of ANE on the expression of complement receptors and Fc receptors were examined using an immunofluorescence staining method followed by flow cytometry and confocal laser scanning microscopy. The phagocytic activity of neutrophils against complement or immunoglobulin (Ig)G-opsonized fluorescent beads was analyzed using flow cytometry. Expression of F-actin was determined using confocal laser scanning microscopy.

RESULTS

ANE significantly inhibited the production of complement receptors (CR1, CR3, and CR4) and Fc receptors (FcγRII and FcγRIII) in a concentration-dependent manner. Treatment of neutrophils with ANE significantly impaired their ability to phagocytose fluorescent beads. ANE also inhibited phagocytosis of fluorescent beads that were opsonized by complement or IgG. Moreover, expression of F-actin was inhibited after ANE treatment.

CONCLUSIONS

ANE inhibits the complement- and IgG-mediated neutrophil phagocytosis that may result from reduction of the expression of complement receptors, Fc receptors, and F-actin formation after ANE treatment. The findings suggest that areca nut chewing may jeopardize the defensive functions of neutrophils and affect periodontal health.

Areca nut extract represses migration and differentiation while activating matrix metalloproteinase-9 of normal gingival epithelial cells

BACKGROUND AND OBJECTIVE

Areca (betel) chewing is associated with an increase in the incidence of periodontal diseases. Aberrations in matrix metalloproteinase (MMP) expression have been reported to be associated with periodontal disease. This study investigated the effects of areca nut extract on MMP activity and the phenotype of human gingival epithelial cells.

MATERIAL AND METHODS

Reverse transcription-polymerase chain reaction, western blotting and gelatin zymography were used to assay MMPs. Cell viability, mobility and detachment assays were performed to characterize the phenotypic impact. Confocal microscopy was employed to evaluate cell aggregation and the distribution of E-cadherin and F-actin.

RESULTS

Treatment of gingival epithelial cells with 10 microg/mL of areca nut extract reduced its cell viability. Treatment with 5 and 10 microg/mL of areca nut extract for 24 h activated MMP-9 but not MMP-2 in gingival epithelial cells. This activation could be nuclear factor-kappaB dependent and was abrogated by 10 microM curcumin. Areca nut extract also reduced the migration and detachment of gingival epithelial cells. The differentiated cell-cell contact of gingival epithelial cells was markedly impaired by areca nut extract. This was accompanied by a disruption of distribution of E-cadherin and F-actin.

CONCLUSION

The areca nut extract-mediated activation of MMP-9 in gingival epithelial cells could signify a potential periodontal pathogenesis in areca chewers. The areca nut extract-mediated inhibition of cell viability and migration, together with the changed aggregation in gingival epithelial cells, suggests that impairment of the re-epithelization underlies the process and this, in turn, might exacerbate gingival inflammation.

Eugenol Modulates Cyclooxygenase-2 Expression Through the Activation of Nuclear Factor Kappa B in Human Osteoblasts

Because eugenol is a major component of root canal sealers and retrograde filling materials, its effects on periapical bone healing are therefore of concern. In this study, the effects of eugenol on the activation of nuclear factor kappa B (NF-kappaB) and the expression of cyclooxygenase-2 (COX-2) in human osteoblasts were investigated. The results showed that eugenol activated the nuclear translocation of NF-kappaB. In addition, COX-2 protein expression in osteoblasts was induced by eugenol in a dose-dependent manner. Furthermore, the eugenol-modulated COX-2 expression was inhibited by an NF-kappaB inhibitor, N-acetylcysteine. Taken together, eugenol might induce COX-2 expression through the activation of NF-kappaB in human osteoblasts. These results suggest that eugenol might be involved in periapical healing by impairing the functions of osteoblasts.

Areca nut extracts-activated secretion of leukotriene B4, and phosphorylation of p38 mitogen-activated protein kinase and elevated intracellular calcium concentrations in human polymorphonuclear leukocytes

BACKGROUND AND OBJECTIVE

Polymorphonuclear leukocytes are the major source of leukotriene B4, which is synthesized via the 5-lipoxygenase pathway. Activation of the 5-lipoxygenase pathway is regulated by intracellular calcium and the phosphorylation of p38 mitogen-activated protein kinase (MAPK). The impact of areca nut extracts on the biosynthesis of leukotriene B4 by human polymorphonuclear leukocytes was evaluated, and some of the possible mechanisms underlying the responses were examined.

MATERIAL AND METHODS

Polymorphonuclear leukocytes were treated with various concentrations of areca nut extracts. The concentrations of leukotriene B4 released into the supernatants were evaluated using enzyme immunoassay. The phosphorylation of p38 MAPK was monitored using immunoblotting, and the cytosolic calcium kinetics were assessed fluorometrically using Fura-2.

RESULTS

Exposure of polymorphonuclear leukocytes to areca nut extracts led to a dose-dependent increase in the production of leukotriene B4, with levels peaking at 30 min and decreasing thereafter. Areca nut extracts enhanced the phosphorylation of p38 MAPK, an enzyme known to activate 5-lipoxygenase. Incubation with areca nut extracts also resulted in a rapid elevation of intracellular calcium concentrations in polymorphonuclear leukocytes. The induction of leukotriene B4 by areca nut extracts was suppressed with the p38 MAPK inhibitor, SB203580, or with the intracellular calcium chelator, BAPTA-AM.

CONCLUSION

The interaction of areca nut extracts with polymorphonuclear leukocytes activated the arachidonic acid metabolic cascade. Incubation of polymorphonuclear leukocytes with areca nut extracts resulted in the activation of intracellular events, such as phosphorylation of p38 MAPK and Ca2+ mobilization, involved in the release of pro-inflammatory lipid mediators. The results of this study emphasize the potential importance of polymorphonuclear leukocytes as a source of leukotriene B4, which may modulate the inflammatory response in areca chewers.

Areca nut extracts reduce the intracellular reactive oxygen species and release of myeloperoxidase by human polymorphonuclear leukocytes

BACKGROUND AND OBJECTIVE

Polymorphonuclear leukocytes (PMN) represent the first line of host defense. Areca nut extract inhibits the bactericidal activity of, and the release of superoxide anion (O2- ) by, PMN. This study investigated the effects of areca nut extract on the intracellular production of reactive oxygen species (ROS) and on the extracellular release of lysosomal enzyme, myeloperoxidase (MPO), by PMN. The effects of arecoline, a principal component of areca nut, were also examined.

MATERIAL AND METHODS

Human PMN were treated with various concentrations of areca nut extract or arecoline followed by treatment with Hanks' balanced salt solution, with or without cytochalasin B and fMet-Leu-Phe (CB/fMLP). The viability of PMN was determined using propidium iodide staining and flow cytometry. The presence of intracellular ROS was determined using 2',7'-dichlorofluorescin diacetate and fluorometry. MPO release was determined using a substrate assay.

RESULTS

Areca nut extract (25 and 50 microg/ml) significantly decreased the viability of PMN. The intracellular levels of ROS and the extracellular release of MPO were induced in PMN by CB/fMLP. Exposure of PMN to areca nut extract (up to 25 microg/ml) or to arecoline (up to 2 mg/ml) did not directly affect the levels of ROS and MPO activity. However, under conditions that did not affect the viability of PMN, the ability of CB/fMLP to trigger production of intracellular ROS and release of MPO in human PMN was significantly suppressed by areca nut extract and arecoline.

CONCLUSION

Areca nut impaired the activation of PMN by CB/fMLP that might decrease the effectiveness of PMN in the host defense. Alternatively, exposure of PMN to areca nut extract could decrease the capacity of PMN to damage tissues.

Enhancing Effects of Areca Nut Extracts on the Production of Interleukin-6 and Interleukin-8 by Peripheral Blood Mononuclear Cells

BACKGROUND

The habit of chewing areca quid (AQ) has been implicated in oral pathogenesis, including periodontal disease. Little is understood about the roles of AQ in the cytokine secretion by immune cells. The study examined the effects of areca nut, the major ingredient of AQ, on the production of interleukin (IL)-6 and IL-8 by peripheral blood mononuclear cells (PBMC), the immunocompetent cells. The possible role of oxidative stress of areca nut was also examined.

METHODS

Extracts of ripe areca nut (rANE) and tender areca nut (tANE) were examined for their cytotoxic effects on human PBMC using the trypan blue exclusion test. The production of IL-6 and IL-8 by ANE-treated PBMC was analyzed using enzyme-linked immunosorbent assay and reverse transcription-polymerase chain reaction. Effects of an antioxidant, pyrrolidine dithiocarbamate (PDTC), on ANE-induced cytokine secretion were also studied.

RESULTS

At the experimental conditions, 20 micro g/ml rANE decreased cell viability significantly, whereas no significant effect of tANE (< or =80 micro g/ml) was observed. Both rANE (< or =20 micro g/ml) and tANE (< or =160 micro g/ml) significantly increased the secretion of IL-6 and IL-8 by PBMC in a dose- and time-dependent manner. The altered mRNA expression of IL-6 by rANE and tANE was also observed. Moreover, the stimulating effects of rANE on cytokine expression in PBMC could be attenuated by PDTC, suggesting that the oxidative stress of rANE may play a role.

CONCLUSIONS

Markedly enhancing effects of ANE on PBMC-released inflammatory cytokines might cause a sustained cytokine-rich inflammatory milieu in oral cavity of AQ chewers. These excessive cytokines from ANE-treated immune cells may impair periodontal health.

Modulation of Phagocytosis, Chemotaxis, and Adhesion of Neutrophils by Areca Nut Extracts

BACKGROUND

A higher prevalence of periodontal diseases among areca chewers than non-areca chewers has been demonstrated. Neutrophils, representing the first line of the host defense mechanism against microbial infection, play important roles in maintaining periodontal health. This study determined the possible effects of areca nut on phagocytosis, chemotaxis, and adhesion of human neutrophils.

METHODS

Aqueous extracts of ripe areca nut without husk (rANE) and fresh and tender areca nut with husk (tANE) were examined for their effects on neutrophil phagocytosis using flow cytometry and confocal laser scanning microscopy. The effects of rANE and tANE on chemotaxis and adhesion of neutrophils to human aortic endothelial cells were examined using fluorescence-labeled neutrophils.

RESULTS

Both rANE and tANE inhibited the phagocytic activity of neutrophils in a dose-dependent manner. The levels of internalized fluorescent bacteria in neutrophils decreased after ANE treatment. However, exposure of neutrophils to rANE and tANE stimulated the chemotaxis activity of neutrophils to N-formyl-Met-Leu-Phe (fMLP) and enhanced adhesion of neutrophils to human aortic endothelial cells in a dose-dependent manner. Moreover, treatment of neutrophils with rANE was more effective than incubation with tANE.

CONCLUSIONS

Components of areca nut inhibited phagocytosis activity of neutrophils but enhanced chemotaxis and adhesion of neutrophils. Alterations in functions of neutrophils may lead to signs of clinical diseases associated with areca chewing. The components in ANEs that are responsible for these observations remain to be elucidated.