Intracellular Porphyromonas gingivalis exploits recycling pathway to exit from infected cells

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Etiologic factors of early-onset periodontal disease in Down syndrome

SummaryIndividuals with Down syndrome often develop extensive gingivitis, and exhibit rapid and generalized periodontal breakdown in early adulthood. Earlier studies reported a significant prevalence of periodontal disease in patients with Down syndrome younger than 30 years old, whereas recent studies have indicated that periodontal disease associated with the syndrome is less severe than formerly thought, likely due to improved dental care at home and the dental office. Although the etiology of the condition is not yet fully elucidated, a number of studies have shown that Down syndrome related periodontitis is caused by such factors as immunological deficiency, poor oral hygiene, fragile periodontal tissue, early senescence, salivary deficiency, and poor masticatory function. In addition, those individuals experience very early colonization by various periodontal pathogens, and exhibit an exaggerated innate immune response to produce inflammatory mediators such as prostaglandin E2 and matrix metalloproteinases. Recent studies regarding Down syndrome cell adhesion molecule (Dscam) provide further evidence for increased susceptibility to bacterial and viral diseases in Down syndrome. In this review, an overview of contemporary findings on the etiology of periodontal disease associated with Down syndrome is presented

The primary structure of superoxide dismutase purified from anaerobically maintained Bacteroides gingivalis

AbstractThe superoxide dismutase (SOD) of Bacteroides gingivalis can use either iron or manganese as a cofactor in its catalytic activity. In this study, the complete amino acid sequence of this SOD purified from anaerobically maintained B. gingivalis cells was determined. The proteins consisted of 191 amino acid residues and had a molecular mass of 21 500. The sequence of B. gingivalis SOD showed 44–51% homology with those for iron-specific SODs (Fe-SODs) and 40–45% homology with manganese-specific SODs (Mn-SODs) from several bacteria. However, this sequence homology was considerably less than that seen among the Fe-SOD (65–74%) or Mn-SOD family (42–60%). This indicates that B. gingivalis SOD, which accepts either iron or manganese as metal cofactor, is a structural intermediate between the Fe-SOD and Mn-SOD families

The effect of cognitive behavioral therapy on future thinking in patients with major depressive disorder: A randomized controlled trial

BackgroundPessimistic thinking about the future is one of the cardinal symptoms of major depression. Few studies have assessed changes in pessimistic thinking after undergoing cognitive behavioral therapy (CBT). A randomized clinical trial (RCT) was conducted with patients diagnosed with major depressive disorder (MDD) to determine whether receiving a course of CBT affects pessimistic future thinking using a future thinking task.MethodsThirty-one patients with MDD were randomly assigned to either CBT (n = 16) or a talking control (TC) (n = 15) for a 16-week intervention. The main outcomes were the change in response time (RT) and the ratio of the responses for positive valence, measured by the future thinking task. Secondary outcomes included the GRID-Hamilton Depression Rating Scale, the Beck Depression Inventory-Second Edition (BDI-II), the Dysfunctional Attitude Scale (DAS), and the word fluency test (WFT).ResultsRegarding the main outcomes, the CBT group showed reduced RT for the positive valence (within-group Cohen’s d = 0.7, p = 0.012) and negative valence (within-group Cohen’s d = 0.6, p = 0.03) in the distant future condition. The ratio of positive valence responses in both groups for all temporal conditions except for the distant past condition increased within group (distant future: CBT: Cohen’s d = 0.5, p = 0.04; TC: Cohen’s d = 0.8, p = 0.008; near future: CBT: Cohen’s d = 1.0, p < 0.001; TC: Cohen’s d = 1.1, p = 0.001; near past: CBT: Cohen’s d = 0.8, p = 0.005; TC: Cohen’s d = 1.0, p = 0.002). As for secondary outcomes, the CBT group showed greater improvement than the TC group regarding the need for social approval as measured by the DAS (p = 0.012).ConclusionPatients with MDD who received CBT showed a reduced RT for the positive and negative valence in the distant future condition. RT in the future thinking task for depressed patients may be a potential objective measure for the CBT treatment process. Because the present RCT is positioned as a pilot RCT, a confirmatory trial with a larger number of patients is warranted to elucidate the CBT treatment process that influences future thinking.Clinical trial registrationhttps://center6.umin.ac.jp/cgi-open-bin/icdr_e/ctr_view.cgi?recptno=R000021028, identifier UMIN000018155

Cigarette smoke extract impairs gingival epithelial barrier function

We previously showed that junctional adhesion molecule 1 (JAM1) and coxsackievirus and adenovirus receptor (CXADR), tight junction-associated proteins, have important roles to maintain epithelial barrier function in gingival tissues. Smoking is considered to be a significant risk factor for periodontal disease. The present study was conducted to examine the effects of cigarette smoke extract (CSE) on JAM1 and CXADR in human gingival epithelial cells. CSE was found to cause translocation of JAM1 from the cellular surface to EGFR-positive endosomes, whereas CXADR did not. Using a three-dimensional multilayered gingival epithelial tissue model, CSE administration was found to increase permeability to lipopolysaccharide and peptidoglycan, whereas overexpression of JAM1 in the tissue model prevented penetration by those substrates. Furthermore, vitamin C increased JAM1 expression, and inhibited penetration of LPS and PGN induced by CSE. These findings strongly suggest that CSE disrupts gingival barrier function via dislocation of JAM1, thus allowing bacterial virulence factors to penetrate into subepithelial tissues. Furthermore, they indicate that vitamin C increases JAM1 expression and prevents disruption of gingival barrier function by CSE.Yamaga S., Tanigaki K., Nakamura E., et al. Cigarette smoke extract impairs gingival epithelial barrier function. Scientific Reports 13, 9228 (2023); https://doi.org/10.1038/s41598-023-36366-z

Saliva and Plasma Reflect Metabolism Altered by Diabetes and Periodontitis

Periodontitis is an inflammatory disorder caused by disintegration of the balance between the periodontal microbiome and host response. While growing evidence suggests links between periodontitis and various metabolic disorders including type 2 diabetes (T2D), non-alcoholic liver disease, and cardiovascular disease (CVD), which often coexist in individuals with abdominal obesity, factors linking periodontal inflammation to common metabolic alterations remain to be fully elucidated. More detailed characterization of metabolomic profiles associated with multiple oral and cardiometabolic traits may provide better understanding of the complexity of oral-systemic crosstalk and its underlying mechanism. We performed comprehensive profiling of plasma and salivary metabolomes using untargeted gas chromatography/mass spectrometry to investigate multivariate covariation with clinical markers of oral and systemic health in 31 T2D patients with metabolic comorbidities and 30 control subjects. Orthogonal partial least squares (OPLS) results enabled more accurate characterization of associations among 11 oral and 25 systemic clinical outcomes, and 143 salivary and 78 plasma metabolites. In particular, metabolites that reflect cardiometabolic changes were identified in both plasma and saliva, with plasma and salivary ratios of (mannose + allose):1,5-anhydroglucitol achieving areas under the curve of 0.99 and 0.92, respectively, for T2D diagnosis. Additionally, OPLS analysis of periodontal inflamed surface area (PISA) as the numerical response variable revealed shared and unique responses of metabolomic and clinical markers to PISA between healthy and T2D groups. When combined with linear regression models, we found a significant correlation between PISA and multiple metabolites in both groups, including threonate, cadaverine and hydrocinnamate in saliva, as well as lactate and pentadecanoic acid in plasma, of which plasma lactate showed a predominant trend in the healthy group. Unique metabolites associated with PISA in the T2D group included plasma phosphate and salivary malate, while those in the healthy group included plasma gluconate and salivary adenosine. Remarkably, higher PISA was correlated with altered hepatic lipid metabolism in both groups, including higher levels of triglycerides, aspartate aminotransferase and alanine aminotransferase, leading to increased risk of cardiometabolic disease based on a score summarizing levels of CVD-related biomarkers. These findings revealed the potential utility of saliva for evaluating the risk of metabolic disorders without need for a blood test, and provide evidence that disrupted liver lipid metabolism may underlie the link between periodontitis and cardiometabolic disease.Sakanaka A., Kuboniwa M., Katakami N., et al. Saliva and Plasma Reflect Metabolism Altered by Diabetes and Periodontitis. Frontiers in Molecular Biosciences, 8, , 742002. https://doi.org/https://doi.org/10.3389/fmolb.2021.742002