Vitamin C influences antioxidative,anti-inflammatory and wound healing markers in smokers’ gingival fibroblasts in vitro

BackgroundSaudi Arabia has an overall smoking rate of 15.9%. The link between smoking and periodontal disease has been studied extensively. It is possible for human gingival fibroblasts to accumulate nicotine intracellularly over a period of four hours. Additionally, unmetabolized nicotine is released into the environment. Tobacco presence can impair tissue inflammation, wound healing, and organ development. To counterbalance tobacco toxins, vitamin C has been added to a variety of products.AimThis study aims to analyze the RNA expression of antioxidant, anti-inflammatory, and wound healing proteins in human gingival fibroblasts from smokers and nonsmokers using polymerase chain reaction.Materials and MethodshGFs were extracted from clinically healthy periodontium sites of adult male subjects. Both heavy cigarette smokers and never-smokers participated as subjects. Cells were cultured and subcultured in supplemented growth medium. Vitamin C was inducted in the medium at the experimental 6th passage. RNA expression analysis (qRT-PCR) was performed to analyze adhesion, proliferation, and extracellular matrix expression.ResultsThe results revealed marked expression of a wound healing gene (VEGF-A) in never-smokers (p value = 0.016). GPX3 and SOD3 represent antioxidants that are highly expressed in treated never-smoker cells. SOD2 significantly increased (p value = 0.016) in smokers after vitamin C exposure. The anti-inflammatory markers IL-6 and IL-8 were lower among smokers than among nonsmokers (p < 0.0001).ConclusionTobacco smoking suppressed gingival fibroblasts' abilities to regenerate, heal, combat inflammation, and resist free radicals. Vitamin C at cellular levels was beneficial and should be considered in the treatment component of smokers in the dental clinic.     

Gene expression of human beta defensins-1 and -2 is significantly reduced in non-inflamed keratinized oral tissue of smokers

ObjectiveThe impact of smoking on the local innate immune response in the oral cavity, and, commonly, on oral health is actively discussed in the scientific literature. The aim of the present study was to evaluate possible effects of smoking on gene expression of human beta-defensin-1 and -2 in human gingival tissue.Material and methodsBiopsies of keratinized gingival tissues were taken from donors (with written informed consent) undergoing routine surgical treatment. Prior to the sample collection, participants with clinically healthy periodontium were classified as smokers (n = 9) or non-smokers (n = 9). Gingival tissue was homogenized, and total RNA was extracted and analysed by real-time RT-PCR for human beta-defensins-1-, -2-, and interleukins IL-1β- and IL-6-, as well as GAPDH-mRNA. The data obtained were analysed for significant differences using the Mann–Whitney-U test.ResultshBD-1- and hBD-2-, as well as IL-1β- and IL-6-mRNA were detected in all gingival samples. Expression of hBD-1 and -2 was significantly reduced by nearly 2.5-fold (p < 0.05; Mann–Whitney) in gingival samples of smokers compared to control group specimens (non-smokers). In contrast, no significant differences of the gene expression of IL-6 and IL-1β were observed in human gingival tissue of smokers and non-smokers.ConclusionThe results presented here suggest that expression of human beta-defensins hBD-1 and -2, and, thus, the basal levels of innate immune defense reactions in the oral cavity are reduced by smoking.     

Does smoking affect gingival crevicular fluid LL-37 levels following non-surgical periodontal treatment in chronic periodontitis?

ObjectiveLL-37 contributes to maintaining the balance between health and disease. Smoking is a risk factor for periodontitis that impairs neutrophil functions. The aim of the present study was to comparatively evaluate gingival crevicular fluid (GCF) LL-37 levels in smoker and non-smoker chronic periodontitis (CP) patients and controls, as well as the effect of non-surgical periodontal treatment on GCF LL-37 levels.DesignThirty-one CP patients (16 smokers, 15 non-smokers) and thirty-one controls (16 smokers, 15 non-smokers) were included in the study. CP patients received non-surgical treatment. GCF LL-37 levels and periodontal parameters were assessed at baseline, 1 and 3 months after completion of non-surgical periodontal treatment. GCF LL-37 levels were analyzed by ELISA.ResultsNo significant difference was observed in GCF LL-37 levels between smoker and non-smoker controls (p > 0.05). Smoker CP group had significantly lower GCF LL-37 level than non-smoker CP group at baseline (p < 0.05). GCF LL-37 levels significantly decreased in non-smoker CP group at first week, 1 and 3 months after completion of non-surgical periodontal treatment (p < 0.05) although no significant decrease in GCF LL-37 levels was observed in smoker CP group (p > 0.05). Periodontal parameters were correlated with GCF LL-37 levels in non-smoker CP group (p < 0.05), but not in smoker CP group (p > 0.05).ConclusionsGCF LL-37 levels do not seem to be affected from smoking in periodontal health. However, smoking might have a suppressive effect on GCF LL-37 levels in CP. Non-surgical treatment is effective in decreasing GCF LL-37 levels in non-smoker CP patients but not in smokers with CP.     

The effect of different cigarette smoking levels on gingival crevicular fluid volume and periodontal clinical parameters in Saudi Arabia

IntroductionPeriodontal disease is a chronic inflammatory condition of the periodontium. It is the main cause of tooth loss and is considered one of the biggest threats to the oral cavity. Tobacco smoking has long been associated with increased risk for periodontal, peri-implant, and other medical diseases.ObjectiveTo evaluate the effect of smoking and its level on periodontal clinical parameters (probing depth (PD), plaque index (PI), gingival index (GI), clinical attachment level (CAL), bleeding on probing (BOP), and the volume of gingival crevicular fluid (GCF)) in healthy and chronic periodontitis individuals.Material and MethodA total of 160 participants were recruited in the present study, who were equally divided into the following five groups: healthy controls (C), healthy smokers (HS), nonsmokers with periodontitis (PNS), light smokers with periodontitis (PLS), and heavy smokers with periodontitis (PHS). GCF volume and periodontal clinical parameters (PD, PI, GI, CAL, and BOP) were assessed for each participant and compared between the study groups.ResultThere was a statistically significant difference in PD, PI, GI, CAL, and BOP between healthy and periodontitis patients (p < 0.001). The mean PI, PD, and CAL were considerably higher in heavy smokers than light smokers and non-smokers (P < 0.001). In contrast, the mean GI and BOP were significantly lower in heavy smokers than in light smokers and non-smokers. There was a statistically significant difference in GCF between healthy and periodontitis patients (p < 0.001). The mean GCF readings were higher in heavy smokers than light smokers or non-smokers (P < 0.001).ConclusionThe present study confirms the influence of smoking on periodontal clinical parameters. Smoking was associated with increased PD, PI, CAL, and GCF readings; however, GI and BOP were decreased in smokers. The number of cigarettes played a key role in the volume of GCF and periodontal clinical parameters.     

Repair genes expression profile of MLH1, MSH2 and ATM in the normal oral mucosa of chronic smokers

ObjectiveThe aim of this study was to evaluate the effect of chronic smoking on the expression profile of the repair genes MLH1, MSH2 and ATM in the normal oral mucosa of chronic smokers and never smokers.Materials and methodsThe sample consisted of thirty exfoliative cytology smears per group obtained from Smokers and Never Smokers. Total RNA was extracted and expression of the MLH1, MSH2 and ATM genes were evaluated by quantitative real-time and immunocytochemistry. The gene and protein expression data were correlated to the clinical data. Gene expression was analyzed statistically using the Student t-test and Pearson’s correlation coefficient, with p < 0.05.ResultsMLH1, MSH2 and ATM genes were downregulated in the smoking group compared to the control with significant values for MLH1 (p = 0.006), MSH2 (p = 0.0001) and ATM (p = 0.0001). Immunocytochemical staining for anti-MLH1, anti-MSH2 and anti-ATM was negative in Never Smokers; in Smokers it was rarely positive. No significant correlation was observed among the expression of MLH1, MSH2, ATM and age, number of cigarettes consumed per day, time of smoking during life, smoking history or levels of CO in expired air.ConclusionThe expression of genes and proteins related to DNA repair mechanism MLH1, MSH2 and ATM in the normal oral mucosa of chronic smokers was reduced.     

Evaluation of Receptor Activator of Nuclear Factor Kappa B Ligand,Osteoprotegerin, Osteopontin,and Tumor Necrosis Factor Alpha on Chronic Apical Periodontitis in Smokers

IntroductionSmoking can be considered a risk factor for chronic apical periodontitis (CAP). This study compared the immunoexpression of biomarkers receptor activator of nuclear factor kappa B ligand (RANKL), osteoprotegerin (OPG), osteopontin (OPN), and tumor necrosis factor alpha (TNF-α) in CAP in smokers and nonsmokers.MethodsTwelve smokers and 12 nonsmokers diagnosed with CAP and indicated for tooth extraction were selected. Exclusion factors were teeth with a diagnosis of root fracture, previous endodontic treatment, or endoperiodontal injury, in addition to individuals with systemic diseases, under 18 years of age, users of anti-inflammatory and/or antibiotics in the last 3 months, and drug users. Specimens were processed for histopathologic and immunohistochemical analysis.ResultsQualitative analysis of RANKL expression showed 66.66% weak/moderate and 33.33% strong in smokers and 100% weak/moderate in nonsmokers. OPG and OPN expressions were 100% negative to focal in the smoker group and 50% negative to focal and 50% weak/moderate in the nonsmoker group. TNF-α was 25% negative to focal and 75% weak/moderate in the smoker group and 33.33% negative to focal and 66.66% weak/moderate in the nonsmoker group. Quantitative analysis of the data using the Mann-Whitney U test showed that there was a significant difference in the immunoexpression of RANKL (P < .05), OPG (P < .05), and OPN (P < .05), but there was no statistical difference in the immunoexpression of TNF-α (P > .05) between the 2 groups.ConclusionsThese findings suggest that smoking is capable of altering the inflammatory response, influencing the evolution of CAP.     

The up-regulation of heme oxygenase-1 expression in human gingival fibroblasts stimulated with nicotine

BACKGROUND: Cigarette smoking is a major risk factor in the development and further progression of periodontal diseases. Heme oxygenase-1 (HO-1) is known as a stress-inducible protein and functions as an antioxidant enzyme. There is limited information on the expression of HO-1 in smoking-associated periodontal disease. OBJECTIVES: The aim of the present study was to investigate the effects of nicotine on the expression of HO-1 protein in cultured human gingival fibroblasts in vitro and further to compare HO-1 expression in gingival tissues obtained from cigarette smokers and non-smokers in vivo. METHODS: Western blot assay was used to investigate the effects on human gingival fibroblasts exposed to nicotine. In addition, antioxidants catalase, superoxide dismutase (SOD), and N-acetyl-l-cysteine (NAC) were added to test how they modulated the effects on nicotine-induced HO-1 expression. Gingival biopsies taken from the flap surgery of 20 male patients with periodontal disease (10 cigarette smokers and 10 non-smokers) were examined by immunohistochemistry. RESULTS: The exposure of quiescent human gingival fibroblasts to 10 mm nicotine resulted in the induction of HO-1 protein expression in a time-dependent manner (p < 0.05). The addition of glutathione (GSH) precursor NAC inhibited the nicotine-induced HO-1 protein expression (p < 0.05). However, SOD and catalase did not decrease the nicotine-induced HO-1 protein expression (p > 0.05). The results from immunohistochemistry demonstrated that HO-1 expression was significantly higher in cigarette smokers (p < 0.05). HO-1 was noted in the basal layers of epithelium, inflammatory cells, and fibroblasts in specimens from cigarette smoking. CONCLUSIONS: Taken together, these results suggest that HO-1 expression is significantly up-regulated in gingival tissues from cigarette smokers, and nicotine may, among other constituents, be responsible for the enhanced HO-1 expression in vivo. The regulation of HO-1 expression induced by nicotine is critically dependent on the intracellular GSH concentration.     

吸烟对牙周炎患者牙龈组织中成纤维细胞及胶原纤维的影响

目的研究吸烟对牙龈成纤维细胞和胶原纤维的影响.方法分别选取12例吸烟和10例不吸烟中重度牙周炎患者以及5例牙周健康者的牙龈组织标本,分为吸烟组、不吸烟组和对照组.通过Masson染色,光镜观察成纤维细胞和胶原纤维的形态及牙龈组织内胶原纤维相对面积的改变;另每组各选取3例标本,在透射电镜下观察牙龈成纤维细胞及胶原纤维的超微结构.结果吸烟牙周炎患者牙龈内胶原纤维破坏程度重于不吸烟组,新生胶原纤维少.吸烟组胶原纤维面积较不吸烟组无显著性差异(P＞0.05);在超微结构上,吸烟与不吸烟牙周炎患者牙龈成纤维细胞均存在明显的变性,吸烟组重于不吸烟组.结论吸烟可能通过对牙龈成纤维细胞和胶原纤维的损伤,降低牙周组织的修复能力.     

Effect of environmental tobacco smoke from smoker parents on gingival pigmentation in children and young adults: a cross-sectional study

Background: Non‐smokers exposed to environmental tobacco smoke (ETS) absorb nicotine and other compounds just as smokers do, and as the exposure to ETS increases, the level of these harmful compounds in the body also increases. The ill effects of ETS range from gingival pigmentation to lung cancer and death. The exposure to ETS is difficult to quantitatively measure and has been approximated by self‐reported estimates, primarily of the smoking history of spouses. However, the documentation of gingival pigmentation in non‐smokers is meager and has remained contentious. We aimed to assess the effects of ETS from smoker parents on gingival pigmentation in children and young adults and assess the urine cotinine levels in these individuals. Methods: A total of 153 non‐smoking participants with ≥1 smoker parent were randomly selected from the outpatient Department of Periodontics, Bangalore Institute of Dental Sciences and Postgraduate Research Center, Bangalore, India. These participants were divided into three groups based on age, and the smoking history of parents was established by an interview with participants and parents. The degree of gingival pigmentation of participants was assessed by using the gingival pigmentation index and a standardized digital oral photograph. A urine analysis was conducted to assess levels of cotinine. The κ statistic was performed for interexaminer agreement, and χ² and Fisher exact tests were used for statistical analyses. Results: The prevalence of gingival pigmentation in passive smokers was statistically significant (P <0.05). Increased levels of urinary cotinine were observed in all three groups with the highest levels in group 3 (19 to 24 years old). Conclusion: This study depicts the effects of ETS on gingival melanin pigmentation.     

Anodized-hydrothermally treated titanium with a nanotopographic surface structure regulates integrin-α6β4 and laminin-5 gene expression in adherent murine gingival epithelial cells

PurposePeri-implant epithelium associated with the structure of the internal basal lamina is in contact with a transmucosal portion of the endosseous implant surface. This contact is important to protect the many complex factors required for the long-term stability and maintenance of the implant. This study investigated the effect of initial adhesion of gingival epithelial cells to anodized-hydrothermally treated commercially pure titanium with nanotopographic structure (SA-treated c.p.Ti). Changes in cell morphology and gene expression of integrin-α6β4 and laminin-5 were assessed.MethodsMurine immortalized gingival epithelial (GE1) cells were cultured for 1–3 days on c.p.Ti, anodic oxide (AO) c.p.Ti, and SA-treated c.p.Ti disks. Cell morphology was analyzed using scanning electron microscopy (SEM). Cell proliferation was analyzed using the WST-1 assay. Integrin-α6β4 and laminin-5 (α3, β3, γ2) mRNA levels were measured using real-time quantitative RT-PCR.ResultsThe GE1 cells appeared flattened with extensions on all disks by SEM analysis. Filopodium-like extensions were bound closely to the nanotopographic structure surface of SA-treated c.p.Ti especially at day 3 of culture. GE1 cell proliferation as well as the expression of integrin-α6β4 and laminin-5 (α3, β3, γ2) mRNAs was significantly higher on SA-treated c.p.Ti than on c.p.Ti and AO c.p.Ti disks after 3 days (P < 0.05).ConclusionsGingival epithelial cells initially attach to a transmucosal portion of SA-treated c.p.Ti implant material and subsequently express the integrin-α6β4 adhesion molecule and the laminin-5 extracellular matrix molecule. This cell behavior may play a key role in maintaining the peri-implant oral mucosal tissue barrier.     

Smoking and caries experience in subjects with various form of periodontal diseases from a teaching hospital clinic

Abstract: Objective: The aim of this study was to assess the relationships between aggressive periodontitis (AgP), caries and smoking. Method and materials: A cross‐sectional study was conducted among patients who were specifically referred to the Dental Teaching Clinic in Irbid, Jordan for periodontal treatment. Self‐administered questionnaire related to socio‐demographic data and smoking habits was completed. The oral hygiene, gingival status, periodontal health and dental status of the participants was determined by using the plaque index of Silness and Loe [Acta Odontol Scand, 22 (1964), 121], the gingival index of Loe and Silness [Acta Odontol Scand, 21 (1963), 233], clinical attachment level (CAL) and decayed, missing and filled teeth (DMFT) index respectively. Result: The prevalence of smoking was greater in chronic periodontitis (CP) group (44.2%) than in either chronic gingivitis (CG) (27.4%) or AgP (29.9%) group. Self‐reported perio‐diseases in the close family was more prevalent (77%) among subjects diagnosed with AgP. The mean plaque scores were significantly higher for smoker than non‐smoker in AgP group only (P = 0.04), with significantly greater plaque and gingival scores in CG and CP groups than AgP group (P = 0.012, 0.004). A significantly greater mean gingival scores were noted among CG and CP groups than AgP group (P = 0.004). The mean CAL was higher in smokers than in non‐smokers in the three groups, with statistically significant differences in CP and AgP groups (P = 0.04, 0.01 respectively).The mean number of DMFT was significantly higher in smoker than in non‐smoker of all age groups (P = 0.016, 0.043 and 0.01). However, mean DMFT was significantly greater in CP and CG than AgP groups. Conclusion: It was concluded that (i) higher plaque and gingival index among smokers in all groups; (ii) significant difference in the CAL between smoker and non‐smoke in CP and AgP groups; (iii) significant increase in caries risk among smokers in all groups; (iv) smokers and non‐smokers of AgP group had significantly lower mean DMFT scores than those of CG or CP groups.     

Interferon-γ stimulates CD14, TLR2 and TLR4 mRNA expression in gingival fibroblasts increasing responsiveness to bacterial challenge

ObjectiveTo investigate the potential effects of IFN-03A5 on the responsiveness of human gingival fibroblasts to bacterial challenge.DesignmRNA and protein expression of CD14, TLR2 and TLR4 in human gingival fibroblasts was detected by quantitative polymerase chain reaction (Q-PCR) and flow cytometry. The effect of preincubation with IFN-03A5 on subsequent bacterial LPS-induced expression of IL-6 and IL-8 by gingival fibroblasts was determined by ELISA. Bacterial LPS-induced IκBα degradation in human gingival fibroblasts was investigated by western blot.ResultsHuman gingival fibroblasts express CD14, TLR2 and TLR4 mRNAs. IFN-03A5, but not IL-103B2, induced mRNA expression of all three receptors and the expression of membrane bound CD14 protein. Pre-incubation of fibroblasts with IFN-03A5 and subsequent stimulation with Escherichia coli LPS or Porphyromonas gingivalis LPS led to increased production of IL-6 and IL-8. LPS-induced pro-inflammatory cytokine production was abrogated by a blocking antibody to CD14. Both E. coli LPS and P. gingivalis LPS induced IκBα degradation in human gingival fibroblasts.ConclusionOur data indicate that IFN-03A5 primes human gingival fibroblasts, through the upregulation of CD14 expression, which results in increased responsiveness to bacterial LPS challenge, as determined by pro-inflammatory cytokine production.     

The effect of smoking on epithelial proliferation in healthy and periodontally diseased marginal gingival epithelium

BACKGROUND: Smoking causes an increase in the thickness of gingival epithelium, which is the outcome of increased keratinocyte proliferation or loss. Smoking-related changes in the proliferative activity of the gingival epithelium are largely uncharacterized for periodontal diseases. The aim of the present study was to determine the effects of smoking on the proliferation of the epithelium in periodontally diseased marginal gingiva by comparing the expression patterns of two different proliferation markers. METHODS: Gingival biopsies (N=60) were obtained from smokers who had clinically healthy gingiva (n=10), smokers with gingivitis (n=10), smokers with periodontitis (n=10), non-smokers with clinically healthy gingiva (n=10), non-smokers with gingivitis (n=10), and non-smokers with periodontitis (n=10). The quantitative measurement of maximum epithelial thickness was performed on hematoxylin and eosin-stained sections. The expression patterns for proliferating cell nuclear antigen (PCNA) and Ki67 were evaluated immunohistochemically. RESULTS: The percentage of PCNA-positive cells was higher than the percentage of Ki67-positive cells in all groups (P<0.001). When the mean values of PCNA and Ki67 were compared in each group, a statistically significant difference was observed only in the healthy smoker group (P=0.003). Significant differences in PCNA proliferation indices were only found between the smoker group and the non-smoker healthy group (P=0.015). CONCLUSIONS: Smoking had an affect on the proliferation of cells in the oral gingival epithelium, regardless of periodontal status. The increase in thickness of the epithelium was not associated with smoking; periodontal status and inflammation seemed to be more important factors. Smoking induced the replication activity of gingival epithelium and induced DNA repair.     

N-Acetylcysteine modulates the effects of composites on human gingival keratinocytes

ObjectiveThe aim of this study was to evaluate, if antioxidants, like N-Acetylcysteine, can modulate effects of composite eluates on human gingival keratinocytes.MethodsComposite samples of ceram.x® universal, Filtek? Supreme XTE, and Admira® Fusion were stored 72 h in cell culture medium to prepare eluates, according to ISO 10993-12:2012. Human gingival keratinocytes were exposed to these eluates with or without 3 mM N-Acetylcysteine. Following cell observation by iCELLigence®, exposure periods were determined at 1d and 4d. Cell morphological analysis combined with live/dead staining was performed. Tissue-specific biomarkers of terminal differentiation, Involucrin and Filaggrin, were analyzed by indirect immunofluorescence (IIF) and Western blot (WB). qPCR profiling was performed on genes encoding for: inflammation, apoptosis, turn-over of extracellular matrix, adhesion, proliferation and differentiation. For statistical analysis one-way Anova was used (p < 0.05).ResultsCells exposed to N-Acetylcysteine exhibited morphological changes but no cell death. After adding 3 mM N-Acetylcysteine to HGK cultures, increased fluorescence intensity and protein amounts of Involucrin and Filaggrin indicated enhanced differentiation (p < 0.05). Gene expression was modulated by: (i) composition of the composite eluates, (ii) NAC and (iii) exposure time. Filtek? Supreme XTE showed a significant increased gene expression in inflammatory genes (p < 0.05), which was amplified by the addition of NAC at 1d. Concerning exposure time, modulated gene expression showed eluate dependency, substantiated by Filtek? Supreme XTE modulation at day 1 and Admira® Fusion at day 4.SignificanceN-Acetylcysteine-emerging effects on gingival keratinocytes were threefold: (i) increase of differentiation, (ii) modulation of composite-related effects and (iii) in parts counteraction of eluate-induced effects.     

Effects of mechanical force on primary human fibroblasts derived from the gingiva and the periodontal ligament.

Previous experiments have shown that mechanical stress may alter the interactions between cells and extracellular matrix (ECM). The purpose of our study was to investigate the effects of mechanical load on metabolism and ECM expression of primary human periodontal cells. The influence of gravitational force on proliferation, lactate dehydrogenase (LDH) release, and tenascin expression of gingival (HGF) and periodontal ligament fibroblasts (HPDL), as well as their adhesion to various extracellular matrix (ECM) components, was determined. Cells were centrifuged in microplates or flat tubes for 16 hrs at 217 g. Neither an enhanced release of LDH nor an alteration of cell proliferation could be detected after centrifugation. However, the attachment of loaded gingival and periodontal ligament fibroblasts to all tested ECM components significantly decreased in comparison with controls (Wilcoxon-Mann-Whitney test; HGF, p < 0.05; HPDL, p < 0.01). Tenascin expression of mechanically stressed fibroblasts significantly increased in comparison with controls (p < 0.01).     

Stimulatory effect of Aggregatibacter actinomycetemcomitans DNA on proinflammatory cytokine expression by human gingival fibroblasts

ObjectiveWhile different virulence factors have been reported of Aggregatibacter actinomycetemcomitans (Aa), there is little information about the stimulatory effect of its DNA. The main purpose of this study was to assess the inflammatory response of human gingival fibroblasts (HGFs) stimulated with A. actinomycetemcomitans DNA.DesignCytokine levels of IL-6, IL-1α and TNF-α were measured on the supernatant of HGFs activated with 10, 25, 50 and 100 μg/ml DNA of Aa during 24 h. Primary cultures of HGFs were infected with Aa and its DNA at different times and concentrations to compare its cytotoxic effect. Cell damage and adhesion of Aa to HGFs were evaluated under light microscopy and Scanning electron microscopy respectively.ResultsThere was a statistical difference (p < 0.05) in cytokine expression in HGFs activated by bacterial DNA with a dose dependent on IL-6 expression and a significantly elevated expression of IL-1α and TNF-α compared to Human DNA negative control. Substantial morphological alterations were observed after infection of A. actinomycetemcomitans in HGFs but not with bDNA exposure. Aggregatibacter actinomycetemcomitans showed a high rate of adhesion and cell damage to HGFs after 30 min.ConclusionsGenomic DNA of A. actinomycetemcomitans could be a factor in the pathogenesis of periodontitis that might play a major role in the inflammatory response.     

Expression of ICAM-1 and E-selectin in gingival tissues of smokers and non-smokers with periodontitis.

BACKGROUND: Tobacco smoking affects systemic concentrations of soluble intercellular adhesion molecule (ICAM)-1, but its effect on local expression of adhesion molecules in gingival tissue has not been studied previously. METHODS: E-selectin and ICAM-1 expression on small blood vessel endothelia in gingival biopsies obtained from smokers (n=17) and non-smokers (n=17) with periodontitis was examined with immunohistochemistry. Blood vessels were identified with monoclonal antibody for von Willebrand's factor. RESULTS: A significantly larger number of vessels were observed in inflamed tissues of non-smokers than smokers (P<0.05). The number and proportion of vessels expressing both ICAM-1 and E-selectin was greater in sites with inflammation compared to non-inflamed sites in both smokers and non-smokers (P<0.05). The proportion of the total number of vessels expressing ICAM-1 in non-inflamed sites was greater in non-smokers compared with smokers (P<0.05). CONCLUSIONS: These results suggest that the inflammatory response in smokers with periodontitis may not be accompanied by an equivalent increase in vascularity. Reduced ICAM-1 expression in non-inflamed areas of smokers could reflect a systemic effect of tobacco smoking on ICAM-1 independent of inflammation.     

Smoking among dental students at King Saud University: Consumption patterns and risk factors

ObjectiveTo assess smoking prevalence among dental students at King Saud University (KSU) and to determine possible risk factors of tobacco use.MethodsA self-addressed invitation letter was sent to all dental students (males and females) at KSU requesting participation in this study. Data on smoking habits, associated risk factors, and demographic factors, such as age, marital status, residency status, the student’s year of study, and grade point average, were collected by an electronic self-administered questionnaire sent via email. Data were analyzed using SPSS. Significant differences between different groups were assessed with a Pearson Chi-Square test at α = 0.05. Logistic regression analysis was used to calculate the odds ratio (OR) and 95% confidence interval (95% CI) and to determine the effect of different risk factors on students’ smoking habits.ResultsOf the 600 registered dental students, 400 students responded (230 males, 170 females), representing a response rate of 67%. More male than female students were current smokers (27.6% vs. 2.4%, p < 0.001). Most smokers used shisha tobacco only (N = 35, 51.5%), followed by both shisha tobacco and cigarettes (N = 17, 25%), or cigarettes only (N = 16, 23.5%). Male students were about 4 times more likely to be smokers if all or most of their friends were smokers compared to students who had some friends who smoked (OR = 3.9, 95% CI = 1.9–7.7). A high proportion of current smokers (47.8%) reported stress as the main reason for smoking. Twenty-six percent of dental students (N = 87) who are currently nonsmokers reported that they have used tobacco at some point in their lives. Over two thirds of sampled students (63%) believed that public tobacco usage is not well addressed in the current college curriculum.ConclusionApproximately one in every four male dental students at KSU is a smoker. Having friends who are smokers was the most important risk factor associated with smoking. There is a general belief among dental students that public tobacco use is not well addressed in the dental college curriculum.     

CD99 ligation induces intercellular cell adhesion molecule-1 expression and secretion in human gingival fibroblasts

ObjectiveTo examine CD99 expression and its functional role in ICAM-1 induction in human gingival fibroblasts (HGFs) and human gingival epithelial cells (HGECs) by activating cells with anti-CD99 monoclonal antibody, MT99/3.BackgroundEngagement of CD99 with agonistic antibodies has been shown to regulate immune responses, cell adhesion and migration, and cell death in several studies. Particularly, this engagement results in transendothelial migration of leukocytes mediated by intercellular adhesion molecule-1 (ICAM-1) induction in endothelial cells.MethodsTotal mRNA and protein were isolated from HGFs and HGECs for analyses of CD99 and ICAM-1 expression. Surface expression of CD99 and ICAM-1 was analysed by flow cytometry, and the detection of soluble ICAM-1 was assayed by immunoprecipitation and ELISA.ResultsCD99 surface expression was constitutive on HGFs to a greater extent than that on HGECs. CD99 ligation with MT99/3 induced ICAM-1 mRNA expression in HGFs, but not in HGECs. Interestingly, CD99 ligation led to an increased level of soluble ICAM-1 detected in culture supernatant, whereas interleukin-1β (IL-1β) treatment induced expression of membrane-bound ICAM-1. Furthermore, ICAM-1 induction by CD99 engagement was demonstrated to involve the activation of the p50 subunit of nuclear factor-kappaB (NF-κB), extracellular signal-regulated kinase, and p46 c-Jun N-terminal kinase that differed from that by IL-1β treatment.ConclusionOur study has shown the involvement of CD99 ligation in the up-regulation of ICAM-1 expression and its secretion in gingival fibroblasts, which may be essential for better understanding of the pathogenesis of periodontal disease.