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Genetic risk factors play important roles in the etiology of oral, dental, and craniofacial diseases. Identifying the relevant risk loci and understanding their molecular biology could highlight new prevention and management avenues. Our current understanding of oral health genomics suggests that dental caries and periodontitis are polygenic diseases, and very large sample sizes and informative phenotypic measures are required to discover signals and adequately map associations across the human genome. In this article, we introduce the second wave of the Gene-Lifestyle Interactions and Dental Endpoints consortium (GLIDE2) and discuss relevant data analytics challenges, opportunities, and applications. In this phase, the consortium comprises a diverse, multiethnic sample of over 700,000 participants from 21 studies contributing clinical data on dental caries experience and periodontitis. We outline the methodological challenges of combining data from heterogeneous populations, as well as the data reduction problem in resolving detailed clinical examination records into tractable phenotypes, and describe a strategy that addresses this. Specifically, we propose a 3-tiered phenotyping approach aimed at leveraging both the large sample size in the consortium and the detailed clinical information available in some studies, wherein binary, severity-encompassing, and "precision," data-driven clinical traits are employed. As an illustration of the use of data-driven traits across multiple cohorts, we present an application of dental caries experience data harmonization in 8 participating studies (N = 55,143) using previously developed permanent dentition tooth surface-level dental caries pattern traits. We demonstrate that these clinical patterns are transferable across multiple cohorts, have similar relative contributions within each study, and thus are prime targets for genetic interrogation in the expanded and diverse multiethnic sample of GLIDE2. We anticipate that results from GLIDE2 will decisively advance the knowledge base of mechanisms at play in oral, dental, and craniofacial health and disease and further catalyze international collaboration and data and resource sharing in genomics research. [ABSTRACT FROM AUTHOR]

We evaluate visualization concepts to represent missing values in parallel coordinates. We focus on the trade‐off between the ability to perceive missing values and the concept's impact on common tasks. For this purpose, we identified three missing value representation concepts: removing line segments where values are missing, adding a separate, horizontal axis onto which missing values are projected, and using imputed values as a replacement for missing values. For the missing values axis and imputed values concepts, we additionally add downplay and highlight variations. We performed a crowd‐sourced, quantitative user study with 732 participants comparing the concepts and their variations using five real‐world datasets. Based on our findings, we provide suggestions regarding which visual encoding to employ depending on the task at focus. [ABSTRACT FROM AUTHOR]

Background: Periodontal disease is associated with cardiovascular disease (CVD) but it is unknown if periodontal disease severity is associated with asymptomatic carotid plaque. The aim of the current population-based, observational study was to investigate if signs of periodontal disease are associated with the occurrence of carotid plaque and total plaque area (TPA).Methods: The Malmö Offspring Study (MOS) is a population-based study. MOS participants underwent a thorough cardiovascular phenotyping, including carotid ultrasonography. The Malmö Offspring Dental Study (MODS) invited participants of MOS for dental examination, including periodontal charting. Multivariable regression models were used to analyse the presence of carotid plaque and TPA in relation to periodontal parameters.Results: In all, 831 MODS participants were recruited, out of which 495 belonged to the children generation with mean age of 53 years, 63% had carotid plaque and 38% had moderate or severe periodontal disease. In models adjusted for CVD risk factors, the OR for having carotid plaque in subjects with vs without periodontal disease was 1.75 (95% CI: 1.11-2.78). In a linear model with TPA as dependent and number of periodontal pockets ≥ 4 mm as independent variable, the adjusted beta-coefficient was 0.34 mm2 (95% CI 0.16-0.52).Conclusion: Individuals within the highest quartile of periodontal pockets are expected to have 9 mm2 larger TPA compared to those without pockets. Our results suggest that intervention studies addressing periodontal disease could be useful for prevention of CVD. [ABSTRACT FROM AUTHOR]

Background and Objective The aim of this study was to assess the impact of 1α,25-dihydroxyvitamin D3 (vitamin D3) on osteogenic and inflammatory properties of human periodontal ligament ( PDL) cells and investigate underlying mechanisms. Material and Methods Human PDL cells, obtained from four subjects, were stimulated with vitamin D3 for 4-48 h. The bone markers osteopontin and osteocalcin and proinflammatory cytokine/chemokine expression was determined by quantitative real-time polymerase chain reaction and enzyme-linked immunosorbent assay. Cytokine and chemokine expression was determined after stimulation with the inflammation promoter lipopolysaccharide ( LPS) in the presence or absence of vitamin D3. Alkaline phosphatase activity was assessed using p-nitrophenylphosphate substrate. Results Treatment with 30 ng/m L of vitamin D3, corresponding to an optimal plasma concentration of vitamin D, for 24 h had no effect on PDL cell number and morphology but increased PDL cell osteopontin and osteocalcin m RNA expression by about 70 and 40%, respectively, and, moreover, treatment with vitamin D3 for 48 h enhanced PDL cell alkaline phosphatase activity by about two times showing that vitamin D3 exerts pro-osteogenic effects in human PDL cells. Stimulation with LPS (1 μg/m L) for 4 h increased PDL cell interleukin ( IL)-6 cytokine and chemokine ligand 1 ( CXCL1) chemokine m RNA expression several fold. The LPS-induced increase in IL-6 and CXCL1 transcripts was attenuated by vitamin D3 (30 ng/m L). Treatment with vitamin D3 (3-300 ng/m L) for 24 h reduced the LPS-evoked increase in PDL cell IL-6 protein by about 50%. Vitamin D3 (30 ng/m L) had no effect on LPS-induced IL-1β and MCP-1 m RNA expression. Conclusions Vitamin D3 promotes osteogenic differentiation but also downregulates inflammation promoter-induced IL-6 cytokine and CXCL1 chemokine expression in human PDL cells, suggesting that vitamin D3 both stimulates bone regeneration and antagonizes inflammation in human periodontal tissue. [ABSTRACT FROM AUTHOR]

Background and Objective The aim of this study was to assess the impact of 1α,25-dihydroxyvitamin D3 (vitamin D3) on osteogenic and inflammatory properties of human periodontal ligament ( PDL) cells and investigate underlying mechanisms. Material and Methods Human PDL cells, obtained from four subjects, were stimulated with vitamin D3 for 4-48 h. The bone markers osteopontin and osteocalcin and proinflammatory cytokine/chemokine expression was determined by quantitative real-time polymerase chain reaction and enzyme-linked immunosorbent assay. Cytokine and chemokine expression was determined after stimulation with the inflammation promoter lipopolysaccharide ( LPS) in the presence or absence of vitamin D3. Alkaline phosphatase activity was assessed using p-nitrophenylphosphate substrate. Results Treatment with 30 ng/m L of vitamin D3, corresponding to an optimal plasma concentration of vitamin D, for 24 h had no effect on PDL cell number and morphology but increased PDL cell osteopontin and osteocalcin m RNA expression by about 70 and 40%, respectively, and, moreover, treatment with vitamin D3 for 48 h enhanced PDL cell alkaline phosphatase activity by about two times showing that vitamin D3 exerts pro-osteogenic effects in human PDL cells. Stimulation with LPS (1 μg/m L) for 4 h increased PDL cell interleukin ( IL)-6 cytokine and chemokine ligand 1 ( CXCL1) chemokine m RNA expression several fold. The LPS-induced increase in IL-6 and CXCL1 transcripts was attenuated by vitamin D3 (30 ng/m L). Treatment with vitamin D3 (3-300 ng/m L) for 24 h reduced the LPS-evoked increase in PDL cell IL-6 protein by about 50%. Vitamin D3 (30 ng/m L) had no effect on LPS-induced IL-1β and MCP-1 m RNA expression. Conclusions Vitamin D3 promotes osteogenic differentiation but also downregulates inflammation promoter-induced IL-6 cytokine and CXCL1 chemokine expression in human PDL cells, suggesting that vitamin D3 both stimulates bone regeneration and antagonizes inflammation in human periodontal tissue. [ABSTRACT FROM AUTHOR]

Background and Objective High levels of the antimicrobial peptide, LL-37, are detected in gingival crevicular fluid from patients with chronic periodontitis. LL-37 not only shows antimicrobial activity but also affects host-cell viability. The objective of the present study was to identify endogenous mechanisms that antagonize the detrimental effects of LL-37 on osteoblast viability, focusing on the human peptide p33 expressed on the surface of various cell types. Material and Methods Human osteoblast-like MG63 cells and human h FOB1.19 osteoblasts were treated with or without LL-37 in the presence or absence of p33. Recombinant human p33 was expressed in an Escherichia coli expression system. Lactate dehydrogenase ( LDH) was assessed using an enzymatic spectrophotometric assay. DNA synthesis was determined by measuring [3 H]-thymidine incorporation. Cell number was assessed by counting cells in a Bürker chamber. Intracellular Ca2+ was monitored by recording Fluo 4- AM fluorescence using a laser scanning confocal microscope. Cellular expression of p33 was determined by western blotting. Results LL-37 caused a concentration-dependent release of LDH from human osteoblasts, showing a half-maximal response value ( EC50) of 4 μ m and a rapid and sustained rise in the intracellular Ca2+ concentration of osteoblasts, suggesting that LL-37 forms pores in the cell membrane. p33 (10 μ m) inhibited the LL-37-induced LDH release and LL-37-evoked rise in intracellular Ca2+ concentration, suggesting that p33 prevents LL-37-induced permeabilization of the cell membrane. Moreover, p33 blocked LL-37-induced attenuation of osteoblast numbers. Also, mucin antagonized, at concentrations representative for nonstimulated whole saliva, LL-37-evoked LDH release, whilst cationic endogenous polyamines had no impact on LL-37-induced LDH release from osteoblasts. Conclusions The endogenous peptide p33 prevents LL-37-induced reduction of human osteoblast viability. Importantly, this mechanism may protect the osteoblasts from LL-37-induced cell damage in patients suffering from chronic periodontitis associated with high levels of LL-37 locally. [ABSTRACT FROM AUTHOR]

Jönsson D, Nilsson B-O. The antimicrobial peptide LL-37 is anti-inflammatory and proapoptotic in human periodontal ligament cells. J Periodont Res 2012; 47: 330-335. © 2011 John Wiley & Sons A/S Background and Objective: The antimicrobial peptide LL-37 is expressed in periodontal tissue, and variations in LL-37 levels have been associated with periodontal disease. The effects of LL-37 on periodontal ligament cell function have not been described before. Here, we assess anti-inflammatory properties of LL-37 and investigate the effects of LL-37 on cell differentiation, cell proliferation and apoptosis in human periodontal ligament cells. Material and Methods: Periodontal ligament cells were obtained from teeth extracted for orthodontic reasons. Cytokine (interleukin-6) and chemokine (monocyte chemoattractant protein-1) expression was determined by quantitative PCR, cell differentiation by alkaline phosphatase activity, cell proliferation by counting cells in a Bürker chamber, DNA synthesis by incorporation of radiolabeled thymidine and apoptosis by cell morphology and activated caspase 3 quantities. Results: Treatment with 0.1 and 1 μ m of LL-37 totally reversed lipopolysaccharide-induced monocyte chemoattractant protein-1 expression and suppressed lipopolysaccharide-induced interleukin-6 expression by 50-70%. LL-37 had no effect on alkaline phosphatase activity. Incubation with 8 μ m LL-37 strongly reduced cell number. DNA synthesis was attenuated by about 90% in response to 8 μ m LL-37, confirming its antiproliferative effect. Cell morphology was altered in an apoptosis-like fashion in cells treated with 8 μ m LL-37. Furthermore, the quantity of activated caspase 3 was increased in cells treated with 1 and 8 μ m of LL-37, suggesting apoptosis. Conclusion: LL-37 strongly attenuates lipopolysaccharide-induced cytokine and chemokine expression and, in high concentrations, reduces cell proliferation through inhibition of DNA synthesis and by promoting apoptosis in human periodontal ligament cells. [ABSTRACT FROM AUTHOR]

. Rafferty B, Jönsson D, Kalachikov S, Demmer RT, Nowygrod R, Elkind MSV, Bush Jr H, Kozarov E. (Columbia University Medical Center, New York, NY; and Weill Cornell Medical College, New York, NY; USA) Impact of monocytic cells on recovery of uncultivable bacteria from atherosclerotic lesions. J Intern Med 2011; 270: 273-280. Objective. Epidemiological evidence suggests that infections may contribute to atherogenesis. However, with the exception of Chlamydophila pneumoniae, cultivable bacteria have not been recovered from atherosclerotic lesions. Therefore, we aimed at developing an approach to recover uncultivable bacteria from atherectomy tissues. Methods. We cultured homogenates from atherectomy specimens from seven nonseptic patients undergoing surgery for arterial obstruction either alone or together with THP-1 monocyte-like cells. We performed 16S rDNA analysis, biochemical tests, random amplification of polymorphic DNA PCR analysis, quantitative polymerase chain reaction (qPCR) and immunohistofluorescence to identify the cultivated bacteria. Wilcoxon signed-rank tests were used to determine whether THP-1 treatment yielded a higher number of isolates than did the untreated controls. Results. We recovered more bacteria from cocultures of atherectomy specimens with THP-1 cells than atherectomy specimens cultured alone. On average, tissue homogenates incubated with THP-1 cells versus control yielded 124 vs. 22 colony-forming units, a median of 140 vs. 7, respectively ( P = 0.02). We recovered 872 isolates of limited number of species, including Propionibacterium acnes, Staphylococcus epidermidis and Streptococcus infantis and the fastidious anaerobe Porphyromonas gingivalis, and confirmed its presence in tissue using double immunofluorescence imaging. qPCR demonstrated the presence of ≥3.5 × 103 P. gingivalis genomes per gram of atheromatous tissue. Conclusions. These results indicate that viable previously uncultivable bacterial species are present within atheromas. Our results suggest revisiting the hypothesis that infections may have a causative role in atherosclerotic inflammation and have implications for research regarding novel diagnostics and treatments for cardiovascular disease. [ABSTRACT FROM AUTHOR]

Jönsson D, Nebel D, Bratthall G, Nilsson B-O. The human periodontal ligament cell: a fibroblast-like cell acting as an immune cell. J Periodont Res 2011; 46: 153-157. © 2010 John Wiley & Sons A/S Periodontal ligament cells are fibroblast-like cells characterized by collagen production but also possessing some osteoblastic features. In the light of numerous studies presented during recent times, which show that human periodontal ligament cells also produce cytokines and chemokines in response to inflammation promoters, it is reasonable to suggest that periodontal ligament cells play a role as promoters of periodontal inflammation through these mechanisms. The periodontal ligament, which harbours the periodontal ligament cells, is a part of the attachment apparatus comprised of periodontal ligament cells, extracellular matrix and fibres, attaching the root cement to the alveolar bone. Periodontal ligament cells are in close proximity to bacteria within the plaque and the pocket, and thus these cells are readily accessible to bacterial endotoxins and other promoters of inflammation. Cytokines and chemokines, released by periodontal ligament cells upon stimulation with inflammation promoters, reach the blood vessels easily thanks to rich vascularization of the periodontium stimulating recruitment of white blood cells to the site of inflammation. In addition to classical inflammatory cells, such as leucocytes, macrophages and mast cells, the periodontal ligament cells also contribute to periodontal inflammation via their production and release of cytokines and chemokines. Therefore, pharmacological treatment of periodontitis should aim to reduce the release of proinflammatory agents not only from classical inflammatory cells but also from periodontal ligament cells. [ABSTRACT FROM AUTHOR]

Nebel D, Jönsson D, Norderyd O, Bratthall G, Nilsson B-O. Differential regulation of chemokine expression by estrogen in human periodontal ligament cells. J Periodont Res 2010; 45: 796-802. © 2010 John Wiley & Sons A/S Estrogen modulates inflammatory responses, but the mechanisms involved have not yet been identified. Periodontal ligament (PDL) cells produce chemokines (a group of chemoattractant molecules that recruit leukocytes) and it has been suggested that estrogen modulates periodontal inflammation by regulating the expression of chemokines by PDL cells. Therefore, the objectives of this study were to investigate the regulation of chemokine ligand 2 [CCL2/monocyte chemoattractant protein 1 (MCP-1)], chemokine ligand 3 [CCL3/macrophage inflammatory protein-1α (MIP-1α)] and chemokine ligand 5 (CCL5/RANTES) by estrogen in human PDL cells. PDL cells were obtained from the PDL of premolars, extracted for orthodontic reasons, from two boys and two girls (16 and 17 years of age). PDL cell CCL2, CCL3 and CCL5 mRNA transcripts were determined by quantitative real-time PCR. The concentrations of CCL2, CCL3 and CCL5 proteins were determined by ELISAs. Treatment with 0.5 μg/mL of lipopolysaccharide (LPS, from Escherichia coli) + 100 n 17β-estradiol (E) for 24 h reduced the expression of CCL3 mRNA by about 40% compared to PDL cells treated with LPS alone. Attenuation of CCL3 mRNA was not associated with a decrease in CCL3 protein within 48 h, suggesting a slow turnover of the CCL3 protein. Interindividual differences in the effects of E on CCL5 mRNA expression were observed. E (100 n) increased the expression of CCL5 by 40-60% in PDL cells derived from two subjects but reduced the expression of CCL5 by about 30% in cells from another subject. CCL2 mRNA and CCL2 protein were highly expressed, but not regulated by E. Similar data were observed in cells obtained from both boys and girls. Regulation, by estrogen, of chemokine expression in PDL cells shows a complex pattern involving the down-regulation as well as the up-regulation of chemokines, suggesting that estrogen exerts both anti-inflammatory and proinflammatory effects through these mechanisms. [ABSTRACT FROM AUTHOR]

Nebel D, Jönsson D, Norderyd O, Bratthall G, Nilsson B-O. Differential regulation of chemokine expression by estrogen in human periodontal ligament cells. J Periodont Res 2010; 45: 796-802. © 2010 John Wiley & Sons A/S Estrogen modulates inflammatory responses, but the mechanisms involved have not yet been identified. Periodontal ligament (PDL) cells produce chemokines (a group of chemoattractant molecules that recruit leukocytes) and it has been suggested that estrogen modulates periodontal inflammation by regulating the expression of chemokines by PDL cells. Therefore, the objectives of this study were to investigate the regulation of chemokine ligand 2 [CCL2/monocyte chemoattractant protein 1 (MCP-1)], chemokine ligand 3 [CCL3/macrophage inflammatory protein-1α (MIP-1α)] and chemokine ligand 5 (CCL5/RANTES) by estrogen in human PDL cells. PDL cells were obtained from the PDL of premolars, extracted for orthodontic reasons, from two boys and two girls (16 and 17 years of age). PDL cell CCL2, CCL3 and CCL5 mRNA transcripts were determined by quantitative real-time PCR. The concentrations of CCL2, CCL3 and CCL5 proteins were determined by ELISAs. Treatment with 0.5 μg/mL of lipopolysaccharide (LPS, from Escherichia coli) + 100 n 17β-estradiol (E) for 24 h reduced the expression of CCL3 mRNA by about 40% compared to PDL cells treated with LPS alone. Attenuation of CCL3 mRNA was not associated with a decrease in CCL3 protein within 48 h, suggesting a slow turnover of the CCL3 protein. Interindividual differences in the effects of E on CCL5 mRNA expression were observed. E (100 n) increased the expression of CCL5 by 40-60% in PDL cells derived from two subjects but reduced the expression of CCL5 by about 30% in cells from another subject. CCL2 mRNA and CCL2 protein were highly expressed, but not regulated by E. Similar data were observed in cells obtained from both boys and girls. Regulation, by estrogen, of chemokine expression in PDL cells shows a complex pattern involving the down-regulation as well as the up-regulation of chemokines, suggesting that estrogen exerts both anti-inflammatory and proinflammatory effects through these mechanisms. [ABSTRACT FROM AUTHOR]

Jönsson D, Wahlin Å, Idvall I, Johnsson I, Bratthall G, Nilsson B-O: Differential effects of estrogen on DNA synthesis in human periodontal ligament and breast cancer cells. J Periodont Res 2005; doi: 10.1111/j.1600-0765.2005.00821.x © Blackwell Munksgaard 2005 It is important to clarify the biological function of the female sex hormones estrogen and progesterone in periodontal ligament cells, as these hormones may affect periodontal health. We have previously shown that human periodontal ligament cells express estrogen receptor β (ERβ) but not ERα, whereas human breast cancer cells (MCF7) express both ERα and ERβ . Data on progesterone receptor (PgR) expression in human periodontal ligament cells have not been reported. Determine PgR expression in human periodontal ligament and MCF7 cells and to investigate how estrogen affects DNA and collagen synthesis in these two cell types showing different pattern of expression for ERα and β. Periodontal ligament cells were obtained from the periodontal ligament of premolars extracted for orthodontic reasons and MCF7 cells from the American Type Culture Collection (ATCC). PgR expression was determined by immunocytochemistry. DNA and collagen synthesis was determined by [3H]thymidine and l-[3H]proline incorporation, respectively. PgR immunoreactivity was observed in nuclei of MCF7 but not periodontal ligament cells. Treatment with estrogen (17β-estradiol, E2) at physiological concentrations for 24 h stimulated DNA synthesis by more than two times in MCF7 cells, whereas there was no effect on periodontal ligament cell DNA synthesis. The ER blocker ICI 182780 fully reversed the stimulatory effect of E2. Not only short-term (24 h) but also long-term (5 days) treatment with E2 lacked effect on DNA synthesis in periodontal ligament cells. Neither periodontal ligament cell viability nor collagen synthesis was affected by E2 treatment. Identical results were observed in periodontal ligament cells from male and female subjects. Human MCF7 but not periodontal ligament cells express PgR, suggesting that progesterone via PgR affects MCF7 but not periodontal ligament cells. Further, estrogen stimulates breast cancer MCF7 cell proliferation, whereas it has no effect on proliferation of periodontal ligament cells, probably reflecting cell type specific ER expression pattern in these two cell types. [ABSTRACT FROM AUTHOR]