[Effects of Porphyromonas gingivalis with different fimA genotypes on vascular cell adhesion molecule-1 and intercellular adhesion molecule-1 production by human umbilical vein endothelial cells].

OBJECTIVE: To investigate the effect of Porphyromonas gingivalis (Pg) with different fimA genotypes on vascular cell adhesion molecule-1 (VCAM-1) and intercellular adhesion molecule-1 (ICAM-1) production by human umbilical vein endothelial cells (HUVEC). METHODS: In the present study, PgATCC33277 (type I fimA genotype), WCSP 115 (type II fimA genotype), W83 (type IV fimA genotype), and Escherichia coli-lipopolysaccharide (Ec-LPS) were designed as experimental group 1, 2, 3, and positive control group, respectively, to stimulate HUVEC, and the un-stimulated HUVEC were analyzed as negative control group. The three strains of Pg were cultured anaerobically in standard condition, and then the Pg cells and Ec-LPS were co-cultured with HUVEC for 2, 6, and 24 h, respectively. The amount of ICAM-1 and VCAM-1 produced by HUVEC was detected with flow cytometry (FCM). The expression of ICAM-1 and VCAM-1 by HUVEC were assayed with confocal laser scanning microscope (CLSM). RESULTS: The expression of ICAM-1 on the surface of HUVEC were intensified after infected by Pg with I, II, and IV fimA genotypes (P < 0.05). The amounts of ICAM-1 were 60.27 ± 5.43, 80.81 ± 1.44, and 85.94 ± 2.56 for Pg with type I fimA genotype, 86.69 ± 8.81, 90.19 ± 0.00, and 96.18 ± 0.48 for Pg with type II fimA genotype, 59.66 ± 0.40, 85.79 ± 4.86, and 96.04 ± 2.07 for Pg with type IV fimA genotype at 2, 6 and 24 h after infection, respectively. The up-regulation effects caused by Pg with type II and IV fimA genotypes were stronger than those caused by Pg with type I fimA genotype at different time points except at 2 h (P < 0.05). Under the present experimental condition, infected by Pg with type I, II and IV fimA genotypes stimulated low expression of VCAM-1 by HUVEC, it showed no significant differences among all the groups (P > 0.05). Expression of ICAM-1 and VCAM-1 in Pg infected HUVEC were confirmed by CLSM. Infection of HUVEC with Pg resulted in more fluorescence staining of ICAM-1 and VCAM-1 compared with that in uninfected HUVEC cultures. CONCLUSIONS: The virulence and pathogenicity of Pg is associated with its fimA genotypes, Pg with type II and IV fimA genes possess stronger ability to stimulate HUVEC to up-regulate the expression of cell adhesion molecules, which may lead to disorders in vascular endothelial function.

[Effect of tea polyphenols on proliferation of human periodontal ligament fibroblasts].

OBJECTIVE: To determine the effect of tea polyphenol (TP) on the proliferation of human periodontal ligament fibroblasts (HPDLFs). METHODS: HPDLFs were primary cultured from tissue explants, and the cells of the 5th to 8th passages were used after immunohistochemical identification (with SABC method) of keratin and vimentin expressions. The cells were divided into 5 groups and treated with TP at 1, 0.5, 0.25, 0.125, and 0.0625 mg/ml, respectively, with another group without TP treatment as the blank control group. Cell counting and MTT colorimetric assay were performed to assess the cell proliferation, and flow cytometry was employed to determine the DNA content of the HPDLFs. RESULTS: Different concentrations of TP all significantly increased the proliferation and DNA synthesis of the HPDLFs (P<0.05), and TP treatment at 0.5 mg/ml for 6 h produced the optimal effect. CONCLUSION: TP has obviously effect in promoting the proliferation of HPDLFs.

[Correlation between levels of fibrinogen, beta455 g/A fibrinogen gene polymorphism and chronic periodontitis].

OBJECTIVE: To investigate the relationship between plasma levels of fibrinogen, the-beta455 G/A fibrinogen gene polymorphism and the severity of periodontal inflammation and to explore the possible role of fibrinogen in the association of periodontitis with coronary heart disease (CHD). METHODS: A total of 121 patients with moderate to severe periodontitis and periodontally healthy and gingivitis controls were enrolled in the study. Peripheral blood samples were collected and the plasma fibrinogen levels were determined by the clotting method of Clauss. Polymerase chain reaction and restriction fragment length polymorphism analysis with Hae III were used to examine the -beta455 G/A fibrinogen gene polymorphism. RESULTS: Fibrinogen levels were significantly higher in moderately or severely chronic periodontitis patients [(3.45 +/- 0.68) g/L] than periodontally healthy and gingivitis controls [(2.47 +/- 0.42) g/L, P < 0.001]. The carrier status of the A allele at position -455 in the beta fibrinogen gene was associated with elevated fibrinogen levels and the frequency of the-A455 allele in the beta fibrinogen gene in the patient group was significantly higher than in the control group (P = 0.032). Carriers of the -A455 allele were about 3-fold more likely to have moderate or severe periodontitis as compare to individuals without the -A455 allele( OR = 3. =135, P= 0.008). CONCLUSIONS: Fg-beta455 G/A polymorphism may contribute to the elevated plasma fibrinogen levels and put individuals at higher risk of having severe periodontitis. As the independent risk factor of CHD, fibrinogen levels and Fg-beta455 G/A polymorphism may play a role in the pathogenesis of periodontitis.