NHANES-based analysis of the correlation between leisure-time physical activity, serum cotinine levels and periodontitis risk.

OBJECTIVE: To investigate the association of leisure-time physical activity and serum cotinine levels with the risk of periodontitis in the general population and to further analyze the interaction between leisure-time physical activity and serum cotinine levels on the risk of periodontitis. METHODS: This was a cross-sectional study, extracting data from 9605 (56.19%) participants in the National Health and Nutrition Examination Survey (NHANES) database from 2009 to 2014, and analyzing the relationship and interaction effects of serum cotinine level, leisure time physical activity, and risk of periodontitis by weighted univariate logistic modeling; Effect sizes were determined using ratio of ratios (OR), 95% confidence intervals (95% CI). RESULTS: 5,397 (56.19%) of 9,605 participants had periodontitis; an increased risk of periodontitis was found in those in the leisure time physical activity intensity < 750 MET × min/week group (OR = 1.44, 95% CI: 1.17-1.78). Serum cotinine levels ≥ 0.05 ng/ml were associated with an increased risk of periodontitis (OR = 1.99, 95% CI: 1.69-2.33). The group with low leisure physical activity and serum cotinine levels ≥ 0.05 ng/ml had an increased risk of periodontitis compared to the group with high leisure physical activity and serum cotinine levels < 0.05 ng/ml (OR = 2.48, 95% CI: 1.88-3.27). Interaction metrics RERI = 0.90 (95% CI: 0.44-1.36) and API = 0.36 (95% CI: 0.18-0.55); CI for SI = 2.55 (95% CI: 1.03-6.28). for API 0.36. CONCLUSION: Leisure time physical activity intensity interacted with smoking exposure on periodontitis risk and may provide the general population with the opportunity to Increasing leisure-time physical activity and smoking cessation may provide recommendations for the general population.

An adaptive parameter selection strategy based on maximizing the probability of data for robust fluorescence molecular tomography reconstruction.

To alleviate the ill-posed of the inverse problem in fluorescent molecular tomography (FMT), many regularization methods based on L2 or L1 norm have been proposed. Whereas, the quality of regularization parameters affects the performance of the reconstruction algorithm. Some classical parameter selection strategies usually need initialization of parameter range and high computing costs, which is not universal in the practical application of FMT. In this paper, an universally applicable adaptive parameter selection method based on maximizing the probability of data (MPD) strategy was proposed. This strategy used maximum a posteriori (MAP) estimation and maximum likelihood (ML) estimation to establish a regularization parameters model. The stable optimal regularization parameters can be determined by multiple iterative estimates. Numerical simulations and in vivo experiments show that MPD strategy can obtain stable regularization parameters for both regularization algorithms based on L2 or L1 norm and achieve good reconstruction performance.

Multi-target reconstruction strategy based on blind source separation of surface measurement signals in FMT.

Fluorescence molecular tomography (FMT) is a promising molecular imaging technique for tumor detection in the early stage. High-precision multi-target reconstructions are necessary for quantitative analysis in practical FMT applications. The existing reconstruction methods perform well in retrieving a single fluorescent target but may fail in reconstructing a multi-target, which remains an obstacle to the wider application of FMT. In this paper, a novel multi-target reconstruction strategy based on blind source separation (BSS) of surface measurement signals was proposed, which transformed the multi-target reconstruction problem into multiple single-target reconstruction problems. Firstly, by multiple points excitation, multiple groups of superimposed measurement signals conforming to the conditions of BSS were constructed. Secondly, an efficient nonnegative least-correlated component analysis with iterative volume maximization (nLCA-IVM) algorithm was applied to construct the separation matrix, and the superimposed measurement signals were separated into the measurements of each target. Thirdly, the least squares fitting method was combined with BSS to determine the number of fluorophores indirectly. Lastly, each target was reconstructed based on the extracted surface measurement signals. Numerical simulations and in vivo experiments proved that it has the ability of multi-target resolution for FMT. The encouraging results demonstrate the significant effectiveness and potential of our method for practical FMT applications.

Quantification of growth factors in advanced platelet-rich fibrin and concentrated growth factors and their clinical efficacy as adjunctive to the GTR procedure in periodontal intrabony defects.

BACKGROUND: The development of platelet concentrated biomaterials has gained increasing awareness for regenerative medicine. With different protocol, derivatives such as advanced platelet-rich fibrin (A-PRF), injected platelet-rich fibrin, and concentrated growth factor (CGF) have been demonstrated effectively in preclinical and clinical studies. The aim of this study was to compare the level of growth factors releasing from A-PRF and CGF, and their clinical efficacy in the regenerative management of intrabony defects (IBDs). METHODS: Thirty-two blood samples were collected from eight healthy donors and assessed for platelet-derived growth factor-αß, vascular endothelial growth factor, bone morphogenetic protein-2, and transforming growth factor-ß1 release at indicated times. In addition, the clinical records of 45 patients (15 per group) who had undergone guided tissue regeneration (GTR) with or without A-PRF/CGF were retrieved. The probing depth (PD) and clinical attachment level (CAL) were recorded preoperatively and 6 months postoperatively. Intrabony component (IC) depth, radiographic bone level (RBL), and bone defect filling were assessed radiographically. RESULTS: A-PRF had a looser fibrin network than the CGF but presented larger amounts of growth factors with a more sustained release period. Although there was no difference in PD reduction, CAL gain, RBL height change and defect filling (%) between A-PRF and CGF group, both achieved a more favorable clinical result in IC height reduction and defect filling (%) than the control. CONCLUSIONS: A-PRF and CGF have the ability to stimulate a continual and steady release of total growth factors over a 14-day period. A-PRF and CGF show a similar effectiveness in periodontal bone regeneration with a potential benefit of improving GTR outcomes in IBD treatment.

Activation of calcium signaling in human gingival fibroblasts by recombinant Porphyromonas gingivalis RgpB protein.

Arginine-specific cysteine proteinases, such as Arg-gingipain B (RgpB), mediate inflammation by activating protease-activated receptors (PARs). Arg-gingipain B is produced by Porphyromonas gingivalis, and is implicated in the causation of periodontal disease. The purpose of the present study was to observe the influence of recombinant RgpB protein (rRgpB) on PAR activation by monitoring intracellular Ca2+ ion concentration ([Ca2+]i) and inositol-1,4,5-triphosphate (IP3) levels in human gingival fibroblasts (HGFs). Our findings showed that rRgpB could cause a transient increase in [Ca2+]i. This increase in [Ca2+]i was completely suppressed by vorapaxar, a PAR-1 antagonist. Recombinant Arg-gingipain B increased the concentration of IP3, reaching a maximum at 60 s after treatment; this was completely inhibited by vorapaxar. We therefore conclude that rRgpB-induced calcium signaling in HGFs is mainly caused by PAR-1 activation. This suggests that PAR-1 activation plays a significant role in chronic inflammatory periodontal disease induced by P. gingivalis RgpB.

Modulation of protease-activated receptor expression by Porphyromonas gingivalis in human gingival epithelial cells.

BACKGROUND: Protease-activated receptors (PARs) are G-protein-coupled receptors with an active role in mediating inflammation, pain and other functions. The oral pathogen Porphyromonas gingivalis (P. gingivalis) secretes proteases that activate PARs. The aim of this study was to elucidate the role of PARs in the pathogenesis of chronic periodontitis by expression analysis of PARs in human gingival epithelial cells (GECs) before and after P. gingivalis supernatants treatment. METHODS: GECs were isolated from healthy human gingival tissue samples. The expression of PARs in GECs was determined by reverse transcription-polymerase chain reaction (RT-PCR) and flow cytometry. The effect of P. gingivalis proteases was investigated by quantitative real-time reverse transcription polymerase chain reaction (QRT-PCR) and flow cytometry. RESULTS: PAR-1, PAR-2, and PAR-3 were expressed in GECs. PAR-4 was not found by both RT-PCR and flow cytometry. Analysis of gene expression using QRT-PCR showed an up-regulation of PAR-2 mRNA in comparison to the untreated control cells (P < 0.05). In contrast, the mRNA expressions of PAR-1 and PAR-3 were significantly down-regulated (P > 0.05) in response to P. gingivalis supernatant compared to that in unstimulated control cells. This effect was abrogated by the protease inhibitor TLCK (P < 0.05). The results of flow cytometry indicated PARs protein levels consistent with mRNA levels in the results of QRT-PCR. CONCLUSIONS: Our study shows that PAR-1, PAR-2 and PAR-3 are expressed in GECs. P. gingivalis proteases play a role in the regulation of innate immune responses in GECs. GECs use PARs to recognize P. gingivalis and mediate cell responses involved in innate immunity.

[Expressions of protease-activated receptors in human gingival fibroblasts and its functions in periodontitis].

OBJECTIVE: To investigate the expression types of protease-activated receptors(PAR) in human gingival fibroblasts(HGF) and the functions of PAR in periodontitis. METHODS: Primary HGF were cultured.Reverse transcription PCR(RT-PCR) was used to detect the expression of PAR in HGF. Recombinant gingipain R (rRgp) was applied to HGF. The change of PAR expression on the cell surface was analyzed by real-time quantitative RT-PCR, and enzyme-linked immunosorbent assay (ELISA) was used to detect the change of the interleukin (IL)-6 production from HGF. The results of RT-PCR and ELISA were statistically analyzed using the two independent samples t-test of SPSS10.0 software. RESULTS: HGF expressed PAR-1 and PAR-3. The expression of PAR-1 and PAR-3 changed after two rRgp treatment with HGF cells. The relative expression of PAR-1 was decreased from 1.04 ± 0.31 to 0.67 ± 0.11 and 0.31 ± 0.11. The relative expression of PAR-3 was decreased from 1.01 ± 0.44 to 0.79 ± 0.13 and 0.44 ± 0.12(P < 0.05). The level of IL-6 was increased after rRgp treatment for 8 h. The control group was (18.77 ± 4.09) µg/L, the rRgp treatment groups were (179.36 ± 15.81) and (320.56 ± 26.19) µg/L respectively. CONCLUSIONS: HGF expressed PAR-1 and PAR-3 and were involved in periodontal inflammation.

PI3K/AKT pathway involvement in the osteogenic effects of osteoclast culture supernatants on preosteoblast cells.

This study aimed to investigate the ability of osteoclasts during bone resorption activities to regulate the differentiation and calcification of osteoblast precursor cells. The bone resorption model was established using in vitro cortical bone slices and mouse RAW264.7 cells, which were differentiated into osteoclasts by stimulation with the receptor activator of nuclear factor-κB ligand and macrophage colony-stimulating factor. Tartrate-resistant acid phosphatase (TRAP) staining, reverse transcriptase-polymerase chain reaction (RT-PCR), and scanning electron microscopy (SEM) were used to detect osteoclast differentiation. The osteoblast precursor cell line MC3T3-E1 was cultured with the bone resorption supernatant (BRS). Involvement of the phosphatidylinositol 3-kinase (PI3K)/AKT pathway in osteogenesis was evaluated by Western blotting, RT-PCR, and ELISA analysis of markers of the early (runt-related transcription factor-2 and alkaline phosphatase) and late (osteocalcin [OCN]) stages of osteogenesis, and Alizarin Red S staining of matrix mineralization. TRAP staining, RT-PCR, and SEM analysis demonstrated the successful establishment of the bone resorption model. Osteoclast BRS effectively increased the differentiation and calcification of MC3T3-E1 cells. Western blot analysis indicated that the BRS enhanced AKT and p-AKT expression levels in MC3T3-E1 cells. Following AKT2 knockdown and treatment with the PI3K/AKT pathway inhibitor LY294002, the expression of OCN in MC3T3-E1 cells was decreased (p<0.05), as was the calcification area (p<0.05). The data obtained in this study indicated that the osteoclast bone resorption medium promoted the differentiation and calcification of MC3T3-E1 cells and that the PI3K/AKT pathway played a role in this process.

[Effect of Porphyromonas gingivalis lipopolysaccharide on induced secretion of inflammatory cytokines by different cell lines].

OBJECTIVE: To determine the effect of Porphyromonas gingivalis lipopolysaccharide (LPS) on induced secretion of inflammatory cytokines by different cell lines. METHODS: LPS of P. gingivalis strain ATCC33277 (Pg-LPS) was extracted with phenol-water method, and identified by Limulus test and infrared spectrum analysis. KB, HGF-1 and THP-1 cells were treated with Pg-LPS of different concentrations and time duration, a commercial LPS of E.coli strain O111:B4 (E-LPS) was used as the control. TNF-alpha, IL-1beta, IL-6 and IL-8 levels in culture supernatants were measured by quantitative ELISA. RESULT: The minimal dosages of both Pg-LPS and E-LPS to solidify Limulus agents were 15 ng/ml and their infrared spectrums were similar. With the treatment of Pg-LPS or E-LPS, the TNF-alpha and IL-1beta levels secreted by HGF-1 cells were remarkably increased with a single perk (P<0.01) while a continuous enhancement of secretion by THP-1 cells was observed (P<0.01). Either Pg-LPS or E-LPS stimulated HGF-1 or THP-1 cells to continuously increase the secretion of IL-6 (P<0.01). Both Pg-LPS and E-LPS induced IL-8 secretion by THP-1 cells (P<0.01), but only Pg-LPS showed the similar effect on HGF-1 cells (P<0.01). Neither Pg-LPS nor E-LPS induced KB cells to secrete inflammatory cytokines. CONCLUSION: Pg-LPS can promote target cells to increase their secretion of inflammatory cytokines. KB cells can not be used as the target cell to determine inflammation-causing effect of LPS.

Attenuation of EPO-dependent erythroblast formation by death-associated protein kinase-2.

The adult erythron is maintained via dynamic modulation of erythroblast survival potentials. Toward identifying novel regulators of this process, murine splenic erythroblasts at 3 developmental stages were prepared, purified and profiled. Stage-to-stage modulated genes were then functionally categorized, with a focus on apoptotic factors. In parallel with BCL-X and NIX, death-associated protein kinase-2 (DAPK2) was substantially up-modulated during late erythropoiesis. Among hematopoietic lineages, DAPK2 was expressed predominantly in erythroid cells. In a Gata1-IE3.9int-DAPK2 transgenic mouse model, effects on steady-state reticulocyte and red blood cell (RBC) levels were limited. During hemolytic anemia, however, erythropoiesis was markedly deficient. Ex vivo ana-lyses revealed heightened apoptosis due to DAPK2 at a Kit(-)CD71(high)Ter119(-) stage, together with a subsequent multifold defect in late-stage Kit(-)CD71(high)Ter119(+) cell formation. In UT7epo cells, siRNA knock-down of DAPK2 enhanced survival due to cytokine withdrawal, and DAPK2's phosphorylation and kinase activity also were erythropoietin (EPO)-modulated. DAPK2 therefore comprises a new candidate attenuator of stress erythropoiesis.