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Bulletin du Groupement International pour la Recherche Scientifique en Stomatologie et Odontologie
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This is an Open Access Journal

Open Access journal
ISSN (Print) 0250-4693 - ISSN (Online) 1647-1377
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Epigenetic modifications in salivary glands from patients with
Sjögren's syndrome affect cytokeratin 19 expression
- Authors: O.D. Konsta, A. Charras, C. Le Dantec, E. Kapsogeorgeou, A. Bordron, W.H. Brooks, A.G. Tzioufas, J.O. Pers, Y. Renaudineau
  First page: 01
  Abstract: Sjögren’s syndrome (SS) is a chronic autoimmune epithelitis, and several lines of experiments indicate that multifactorial factors contribute to salivary gland epithelial cells (SGEC) dysfunctions including a combination of environmental factors, lymphocytic infiltrations, genetic predispositions as well as epigenetic defects. Such statement is reinforced by the observation that global DNA methylation (5MeCyt) is altered in minor salivary glands from pSS patients and that such defect is associated cytokeratin 19 (KRT19) overexpression. An epigenetic deregulation of the KRT19 gene was further tested by treating the human salivary gland (HSG) cell line with the DNA demethylating agent 5-azacytidin, and with the histone acetylase inhibitor trichostatin A. Blocking DNA methylation, but not histone acetylation, with 5-azacytidin was associated with KRT19 overexpression at both transcriptional and protein level. Next, analysis of the CpG genome-wide methylome array in the KTR19 locus from long term cultured SGEC obtained from 8 pSS patients revealed a more reduced DNA methylation level in those patients with defective global DNA methylation. Altogether, our data, therefore, suggest that alteration of DNA methylation in SGEC may contribute to pSS pathophysiology in part by controlling the expression of KRT19.
  PubDate: 2016-06-28
  Issue No: Vol. 53 (2016)
Intraplaque hemorrhage, a potential consequence of periodontal bacteria
gathering in human carotid atherothrombosis
- Authors: Adrian Brun, Hélène Rangé, Bastien Prouvost, Olivier Meilhac, Mikael Mazighi, Pierre Amarenco, Guy Lesèche, Philippe Bouchard, Jean-Baptiste Michel
  First page: 11
  Abstract: Periodontal diseases are multifactorial inflammatory diseases, caused by a bacterial biofilm involving both innate and adaptative immunity, characterized by the destruction of tooth-supporting tissues. In the context of periodontitis, the spread of weak pathogenic bacteria into the bloodstream has been described. These bacteria will preferentially localize to existing clot within the circulation. Atherothrombosis of the carotid arteries is a local pathology and a common cause of cerebral infarction. Intraplaque hemorrhages render the lesion more prone to clinical complications such as stroke. The main objective of this study is to explore the biological relationship between carotid intraplaque hemorrhage and periodontal diseases. This study included consecutive patients with symptomatic or asymptomatic carotid stenosis, admitted for endarterectomy surgical procedure (n=41). In conditioned media of the carotid samples collected, markers of neutrophil activation (myeloperoxidase or MPO, DNA-MPO complexes) and hemoglobin were quantified. To investigate the presence of DNA from periodontal bacteria in atherosclerotic plaque, PCR analysis using specific primers was performed. Our preliminary results indicate an association between neutrophil activation and intraplaque hemorrhages, reflected by the release of MPO (p<0,01) and MPO-DNA complexes (p<0,05). Presence of DNA from periodontitis-associated bacteria was found in 32/41 (78%) atheromatous plaque samples. More specifically, DNA from Pg, Tf, Pi, Aa was found in 46%, 24%, 34% and 68% of the samples, respectively. Hemoglobin levels were higher in conditioned media in carotid samples where the bacteria were found, but this was not statistically significant. Our data confirm the relationship between intraplaque hemorrhage and neutrophil activation. In addition, the presence of periodontal bacteria DNA in carotid atheromatous plaque, may contribute to this activation. Further analysis is needed to fully explore the raw data and specimens.
  PubDate: 2016-06-28
  Issue No: Vol. 53 (2016)
Expression of phosphate transporters in optimized cell culture models for
dental cells biomineralization
- Authors: Laure Merametdjian, Amandine David, Nina Bon, Greig Couasnay, Jérôme Guicheux, Céline Gaucher, Sarah Beck-Cormier, Laurent Beck
  First page: 16
  Abstract: Phosphate is a key component of dental mineral composition. The physiological role of membrane proteins of dental cells is suspected to be crucial for mineralization mechanisms. Contrary to published data related to calcium, data on regulation of phosphate flux through membrane of mineralizing cells are scarce. To address this lack of data, we studied the expression of six membranous phosphate transporters in two dental cell lines: a rat odontoblastic cell line (M2H4) and a mouse ameloblastic cell line (ALC) for which we optimized the mineralizing culture conditions.
  PubDate: 2016-06-28
  Issue No: Vol. 53 (2016)
Impact of three endocrine disruptors, Bisphenol A, Genistein and
Vinclozolin on female rat enamel
- Authors: K. Jedeon, A. Berdal, A. Babajko
  First page: 28
  Abstract: Concerns about the potential adverse effects
  of endocrine disruptors (EDs) have been increasing
  over the last three decades. Bisphenol
  A (BPA), genistein (G) and vinclozolin (V) are
  three widely used EDs sharing similar effects.
  Since populations are exposed to many diverse
  EDs simultaneously, we demonstrated
  recently their impact alone or combined on
  male rat tooth enamel. The purpose of this
  study was therefore to assess their effects on
  female rat tooth enamel in order to understand
  why they are differentially sensitive. Rats
  were exposed daily in utero and after birth to
  low doses of EDs during the critical fetal and
  suckling periods when amelogenesis takes
  place. Enamel of rats exposed to EDs presented
  opaque areas of hypomineralization. The
  proportion of affected rats was the highest
  in the groups of rats treated with BPA alone
  and higher in males than in females (in all the
  groups). Comparison of enamel key gene expression
  levels showed modulations of Klk4
  and Enamelin in males but no significant variations
  in females. These findings show that
  female rats are less affected than males by
  the three EDs chosen in this study and suggest
  that enamel hypomineralization may differ
  between males and females
  PubDate: 2016-06-28
  Issue No: Vol. 53 (2016)
Mineral density of hypomineralised and sound enamel
- Authors: Elsa Garot, Patrick Rouas, Emmanuel d'Incau, Nicolas Lenoir, David Manton, Christine Couture-Veschambre
  First page: 33
  Abstract: Molar Incisor Hypomineralisation (MIH) is a structural anomaly that affects the quality of tooth enamel and has important consequences for oral health. The developmentally hypomineralised enamel has normal thickness and can range in colour from white to yellow or brown. The purpose of the present study is to compare the mineral density of hypomineralised and normal enamel. The sample included eight MIH teeth from seven patients. MIH teeth were scanned using high resolution microtomography. Non-parametric statistical tests (Wilcoxon test for paired samples) were carried out. Hypomineralised enamel has decreased mineral density (mean 19%; p < 0.0001) compared to normal enamel. This weak enamel has implications in clinical management of MIH lesions.
  PubDate: 2016-06-28
  Issue No: Vol. 53 (2016)
A standardized procedure to obtain mesenchymal stem/stromal cells from
minimally manipulated dental pulp and Wharton’s jelly samples
- Authors: M. Ducret, H. Fabre, O. Degoult, G. Atzeni, C. McGuckin, N. Forraz, F. Mallein-Gerrin, E. Perrier-Groult, J.C. Fargues
  First page: 37
  Abstract: Transplantation of mesenchymal stem/stromal
  cells (MSCs) has emerged as an effective
  method to treat diseased or damaged
  organs and tissues, and hundreds of clinical
  trials using MSCs are currently under way to
  demonstrate the validity of such a therapeutic
  approach. However, most MSCs used for clinical
  trials are prepared in research laboratories
  with insufficient manufacturing quality control.
  In particular, laboratories lack standardized
  procedures for in vitro isolation of MSCs from
  tissue samples, resulting in heterogeneous
  populations of cells and variable experimental
  and clinical results.
  MSCs are now referred to as Human Cellular
  Tissue-based Products or Advanced Therapy
  Medicinal Products, and guidelines from
  the American Code of Federal Regulation of
  the Food and Drug Administration (21 CFR
  Part 1271) and from the European Medicines
  Agency (European Directive 1394/2007) define
  requirements for appropriate production of
  these cells. These guidelines, commonly called
  “Good Manufacturing Practices” (GMP),
  include recommendations about laboratory
  cell culture procedures to ensure optimal reproducibility,
  efficacy and safety of the final
  medicinal product. In particular, the Food and
  Drug Administration divides ex vivo cultured
  cells into “minimally” and “more than minimally”
  manipulated samples, in function of the
  use or not of procedures “that might alter the
  biological features of the cells”. Today, minimal
  manipulation conditions have not been
  defined for the collection and isolation of
  MSCs (Torre et al. 2015)(Ducret et al. 2015).
  Most if not all culture protocols that have been
  reported so far are unsatisfactory, because
  of the use of xeno- or allogeneic cell culture
  media, enzymatic treatment and long-term
  cell amplification that are known to alter the
  quality of MSCs.
  The aim of this study was to describe a standardized
  procedure for recovering MSCs with
  minimal handling from two promising sources,
  the dental pulp (DP) and the Wharton’s jelly
  (WJ) of the umbilical cord. The quality and homogeneity
  of the expanded cell populations
  were assessed by using flow cytometry with
  criteria that go beyond the International Society
  of Cellular Therapy (ISCT) guidelines for
  MSC characterization.
  PubDate: 2016-06-28
  Issue No: Vol. 53 (2016)