Effect of high glucose, Porphyromonas gingivalis lipopolysaccharide and advanced glycation end-products on production of interleukin-6/-8 by gingival fibroblasts.

BACKGROUND AND OBJECTIVE: It is known that chronic periodontal infection can magnify the cytokine responses in patients with diabetes. Hyperglycemia increases the proinflammatory status, including the levels of advanced glycation end-products (AGEs), in patients with periodontitis. However, whether AGEs have additional effects on the production of those proinflammatory cytokines in diabetic patients with periodontitis is still unknown. To examine in vitro the effect of hyperglycemia and AGEs on the amounts of interleukin (IL)-6 and IL-8 produced in periodontally infected gingiva, human gingival fibroblasts (HGFs) were stimulated with glucose, AGE-modified bovine serum albumin (AGE-BSA) and Porphyromonas gingivalis LPS in the present study. MATERIAL AND METHODS: Primary culture of HGFs was incubated with various concentrations of AGE-BSA (0, 50, 100 and 200 µg/mL) and LPS (0, 10, 100 or 1000 ng/mL) at two different glucose concentrations - normal glucose (5 mm) and high glucose (25 mm). The amounts of IL-6 and IL-8 produced by HGFs were evaluated using ELISA. Expression of the AGE receptor on HGFs was determined by flow cytometry. RESULTS: High glucose stimulated a significant increase in the production of IL-6 and IL-8 by HGFs compared with normal glucose. This enhanced production of IL-6 and IL-8 could also be observed in the presence of LPS and/or AGE-BSA. When both LPS and AGE-BSA were present, especially at high concentrations (≥ 500 µg/mL of LPS and ≥ 25 µg/mL of AGE-BSA), a synergistic effect on IL-8 production was found in the high-glucose condition. CONCLUSIONS: A synergistic effect of the production of IL-8 could be induced in HGFs with the combination of high glucose, LPS and AGEs.

The effects of diallyl sulfide upon Porphyromonas gingivalis lipopolysaccharide stimulated proinflammatory cytokine expressions and nuclear factor-kappa B activation in human gingival fibroblasts.

BACKGROUND AND OBJECTIVE: Diallyl sulfide (DAS), a flavor compound from garlic, has varied potential therapeutic activities. Periodontitis is a disease that develops because of host-mediated inflammation to periodontal pathogens. In this study, the effects of DAS on the common proinflammatory cytokines and nuclear factor-kappa B (NF-κB) in human gingival fibroblasts (HGFs) being stimulated with lipopolysaccharide from Porphyromonas gingivalis, a potent periodontal pathogen, were evaluated. MATERIAL AND METHODS: Cytotoxicities of DAS and lipopolysaccharide on HGFs were measured with MTS assay. The mRNA and protein expressions of proinflammatory cytokines, including interleukin (IL)-1ß, IL-6 and tumor necrosis factor (TNF)-α, from the HGFs treated with lipopolysaccharide with and without DAS were examined with reverse transcription-polymerase chain reaction and immunocytochemistry, respectively. In addition, the activation and nuclear translocation of NF-κB with and without DAS were compared. RESULTS: DAS and lipopolysaccharide treatments within 3 mm and 10 µg/mL, respectively, did not affect the survival rate of HGFs. Lipopolysaccharide (1 µg/mL) significantly increased the mRNA expressions of IL-1ß, IL-6 and TNF-α; however, DAS (1 mm) inhibited these expressions. The protein expressions of TNF-α, IL-1ß, as well as the NF-κB nuclear translocation were increased after lipopolysaccharide treatment, but decreased when there was a DAS pretreatment. CONCLUSION: DAS diminished P. gingivalis lipopolysaccharide-stimulated cytokine expression and NF-κB activation in HGFs; we therefore suggest DAS may be beneficial on periodontal inflammation.

Effect of cyclosporine-A on orthodontic tooth movement in rats.

OBJECTIVE: The objective of this study is to examine the effect of cyclosporine-A (CsA) on the rate of orthodontic tooth movement in rats. SETTING AND SAMPLE POPULATION: This is a randomized controlled trial with a split-mouth design in Sprague-Dawley rats. MATERIAL AND METHODS: Eighteen rats, divided at random in two groups, were fed with 8 mg/kg CsA (experiment) or mineral oil (control) daily after initial healing of bilateral maxillary second molar removal. All rats received orthodontic coil springs (10 cN) secured to the maxillary incisors and first molars at the rights side, while no springs were placed at the left. Distances between first and third molars were measured on days 0, 3, 6, and 12. After sacrificing on day 12, the alveolar ridges of the maxillae were sectioned and blood samples were collected for serum tartrate-resistant acid phosphatase (TRAP)-5b level detection and for histology, respectively. RESULTS: Significantly larger changes in intermolar distances were found after orthodontic force application in the CsA group at days 3 and 12 when compared with the control group. The inter-radicular dental alveolus of CSA-fed rats was osteopenic. Significantly increased TRAP-5b serum level was noted in the CsA group when compared with the control group. CONCLUSIONS: We suggest that CsA enhanced the rate of orthodontic tooth movement. The osteopenia and the increased osteoclastic activity could be the underlying factors.

Nrf-2 regulates cyclosporine-stimulated HO-1 expression in gingiva.

Cyclosporine-A (CsA) stimulates heme oxygenase-1 (HO-1) expression in the gingiva, but the regulation and the role of HO-1 in gingival overgrowth are not well-understood. HO-1 is regulated by several transcription factors, such as nuclear factor-κB (NF-κB) and nuclear factor erythroid-2-related factor 2 (Nrf-2). The aim of this study was to examine the role of Nrf-2 in the regulation of CsA-stimulated HO-1 expression in human gingival fibroblasts. Nrf-2 siRNA (siNrf-2), NF-κB, kinase inhibitors, and sulforaphane (SFN) were used to examine the nuclear translocation of Nrf-2 and expression of HO-1 and transforming growth factor-ß1 (TGF-ß1) in cells. Treatment with siNrf-2, but not with an NF-κB inhibitor, reduced CsA-stimulated HO-1 mRNA expression. ERK inhibition significantly decreased CsA-stimulated Nrf-2 nuclear translocation and HO-1 mRNA expression. Pre-treatment with SFN showed that HO-1 plays a role in attenuating CsA-mediated TGF-ß1 expressions. These findings suggest that CsA-stimulated HO-1 expression is mediated through the activation of ERK, and that Nrf-2 plays a protective role against CsA-induced gingival fibrosis by modulating collagen turnover-related genes.

Expression and bioactivities of endothelin-1 in gingiva during cyclosporine A treatment.

BACKGROUND AND OBJECTIVE: This study aimed to evaluate the expression and bioactivities of endothelin-1 (ET-1) in gingiva during cyclosporine A (CsA) treatment. MATERIAL AND METHODS: After establishing edentulous ridges, experimental rats were fed 30 mg/kg/day CsA while control animals received mineral oil for 4 weeks, after which a reverse transcription-polymerase chain reaction (RT-PCR) and/or immunohistochemistry was used to examine the expression of ET-1, its receptors, proliferating cell nuclear antigen (PCNA) and inducible nitric oxide synthase (iNOS) in gingivae. The roles of the endothelin receptors A and B (ET(A) and ET(B)) in CsA-enhanced expression of PCNA and iNOS were examined in cultured human gingival fibroblasts pretreated with receptor antagonists, by immunocytochemistry and RT-PCR, respectively. RESULTS: The mRNA expression of ET-1, ET(A) and ET(B), as well as of PCNA and iNOS, was significantly greater in edentulous gingiva that received CsA compared with control gingiva. Immunohistochemistry revealed more cells positively stained for ET-1 and its receptors in the tissues of CsA-treated rats than in those of control rats. In fibroblast cultures, enhanced mRNA expression of ET-1, ET(A) and ET(B) was observed after CsA treatment at the concentrations of 10 and 100 ng/mL. Cyclosporine A-enhanced PCNA expression was somewhat reduced by blockade of ET(A), but not ET(B), whereas iNOS expression was somewhat reduced by blockade of ET(B). CONCLUSION: Based on the present findings, we suggest that: (1) CsA upregulates the gingival expression of ET-1 and its receptors; and (2) ET(A) and ET(B) have different bioactivities, ET(A) being involved in cell proliferation and ET(B) being associated with iNOS expression.

Cyclosporin-A inhibits the expression of cyclooxygenase-2 in gingiva.

BACKGROUND AND OBJECTIVE: Various inflammatory mediators are involved in the development of cyclosporine A-induced gingival overgrowth. In this study, the gingival expression of cyclooxygenase-2 after cyclosporine A therapy was examined in vivo and in vitro. MATERIAL AND METHODS: After edentulous ridges on maxilla were established, 21 Sprague-Dawley rats received cyclosporine A daily for 4 wk, and a further 21 rats received solvent. After the rats were killed, the expression of cyclooxygenase-2 mRNA, interleukin-1beta mRNA, tumor necrosis factor-alpha mRNA, and interleukin-6 mRNA was examined in the edentulous gingiva. The expression of cyclooxygenase-2 protein and the production of prostaglandin E2 were also evaluated. RESULTS: In cultured human gingival fibroblasts and epithelial cells, the expression of cyclooxygenase-2 mRNA was measured after treatment with cyclosporine A. Significantly lower expression of cyclooxygenase-2 and interleukin-1beta mRNA, but higher interleukin-6 expression, were observed in gingiva from cyclosporine A-treated rats than in those from the control rats. Significantly less prostaglandin E2 production was observed in cyclosporine A-treated rats. Immunohistochemistry revealed that fewer gingival stromal cells were positively stained for cyclooxygenase-2 in cyclosporine A-treated rats. In cultured cells, significantly less cyclooxygenase-2 mRNA was detected after treatment with cyclosporine A. CONCLUSION: The expression of cyclooxygenase-2 was lower in the plaque nonretentive gingivae and the in vitro gingival cells upon treatment with cyclosporine A. Thus, we propose that cyclosporine A inhibits the expression of gingival cyclooxygenase-2.

Comparison of the efficacy and tolerability of telmisartan 40 mg vs. enalapril 10 mg in the treatment of mild-to-moderate hypertension: a multicentre, double-blind study in Taiwanese patients.

The purpose of this randomised, double-blind, double-dummy, parallel-group study was to evaluate the efficacy and tolerability of telmisartan 40 mg once daily vs. enalapril 10 mg once daily in 147 Taiwanese patients with mild-to-moderate essential hypertension (diastolic blood pressure [DBP] 90-109 mmHg). After 6 weeks' treatment, telmisartan produced a significantly greater reduction from baseline in the primary endpoint of trough seated DBP compared with enalapril 10 mg (11.7 vs. 8.7 mmHg, respectively; p = 0.02). Numerically greater reductions compared with baseline in seated systolic blood pressure (SBP), standing DBP, and standing SBP were achieved with telmisartan compared with enalapril. Also, numerically greater proportions of patients achieved blood pressure control (DBP/systolic blood pressure [SBP] <90/140 mmHg) and responded to treatment (reduction from baseline in trough seated DBP > or = 10 mmHg and/or post-treatment DBP <90 mmHg; reduction from baseline in trough seated SBP > or = 10 mmHg and/or post-treatment SBP <140 mmHg) with telmisartan 40 mg compared with enalapril 10 mg. Although both treatments were well tolerated, the incidence of cough was markedly lower with telmisartan 40 mg (8.5%) than with enalapril 10 mg (18.4%) in this population of Taiwanese hypertensive patients.

Resveratrol inhibition of herpes simplex virus replication.

Resveratrol, a phytoalexin, was found to inhibit herpes simplex virus types 1 and 2 (HSV-1 and HSV-2) replication in a dose-dependent, reversible manner. The observed reduction in virus yield was not caused by the direct inactivation of HSV by resveratrol nor inhibition of virus attachment to the cell. The chemical did, however, target an early event in the virus replication cycle since it was most effective when added within 1 h of cell infection, less effective if addition was delayed until 6 h post-infection and not effective if added 9 h post-infection. Resveratrol was also found to delay the cell cycle at S-G2-M interphase, inhibit reactivation of virus from latently-infected neurons and reduce the amount of ICP-4, a major immediate early viral regulatory protein, that is produced when compared to controls. These results suggest that a critical early event in the viral replication cycle, that has a compensatory cellular counterpart, is being adversely affected.

Inducibility of aryl hydrocarbon hydroxylase in BALB/c/ki mice exposed to urban air pollution.

In two separate experiments BALB/c/ki mice were exposed to urban air pollution. Mice exposed to clean air served as controls. In both experiments there were no obvious quantitative or qualitative differences in lung or liver tissue examined by light microscopy. In both experiments higher aryl hydrocarbon hydroxylase activities and higher trace metal concentrations were observed in the mice exposed to polluted urban air. These data are interpreted in terms of health hazards of urban air pollutants.