title: Free DNA precipitates calcium phosphate apatite crystals in the arterial wall in vivo.
abstract: The arterial wall calcium score and circulating free DNA levels are now used in clinical practice as biomarkers of cardiovascular risk. Calcium phosphate apatite retention in the arterial wall necessitates precipitation on an anionic platform. Here, we explore the role of tissue-free DNA as such a platform.
  
  
  
  The first step consisted of histological observation of samples from human and rat calcified arteries. Various stains were used to evaluate colocalization of free DNA with calcified tissue (alizarin red, fluorescent Hoechst, DNA immunostaining and TUNEL assay). Sections were treated by EDTA to reveal calcification background. Secondly, a rat model of vascular calcifications induced by intra-aortic infusions of free DNA and elastase + free DNA was developed. Rat aortas underwent a micro-CT for calcium score calculation at 3 weeks. Rat and human calcifications were qualitatively characterized using μFourier Transform Infrared Spectroscopy (μFTIR) and Field Emission-Scanning Electron Microscopy (FE-SEM).
  
  
  
  Our histological study shows colocalization of calcified arterial plaques with free DNA. In the intra-aortic infusion model, free DNA was able to penetrate into the arterial wall and induce calcifications whereas no microscopic calcification was seen in control aortas. The calcification score in the elastase + free DNA group was significantly higher than in the control groups. Qualitative evaluation with μFTIR and FE-SEM demonstrated typical calcium phosphate retention in human and rat arterial specimens.
  
  
  
  This translational study demonstrates that free DNA could be involved in arterial calcification formation by precipitating calcium phosphate apatite crystals in the vessel wall.
authors.affiliation: UMR 1148, Inserm-Paris7, Denis Diderot University, Xavier Bichat Hospital, 75018 Paris, France; UMR 1173, Inserm-Paris11, Faculty of Health Sciences Simone Veil, Versailles Saint-Quentin-en-Yvelines University, Paris-Saclay University, 78180 Montigny-le-Bretonneux, France; Department of Vascular Surgery, Ambroise Paré University Hospital, AP-HP, 92104 Boulogne-Billancourt, France; UMR 1018, Inserm-Paris11, CESP, Versailles Saint-Quentin-en-Yvelines University, Paris-Saclay University, Paul Brousse Hospital, 94807 Villejuif, France. Electronic address: rcoscas@gmail.com.
authors.forename: Raphaël
authors.initials: R
authors.lastname: Coscas
authors.affiliation: UMR 1148, Inserm-Paris7, Denis Diderot University, Xavier Bichat Hospital, 75018 Paris, France; Jules Verne University of Picardie and Department of Vascular Surgery, Amiens-Picardie University Hospital, 80054 Amiens, France.
authors.forename: Marie
authors.initials: M
authors.lastname: Bensussan
authors.affiliation: UMR 1148, Inserm-Paris7, Denis Diderot University, Xavier Bichat Hospital, 75018 Paris, France.
authors.forename: Marie-Paule
authors.initials: MP
authors.lastname: Jacob
authors.affiliation: UMR 1148, Inserm-Paris7, Denis Diderot University, Xavier Bichat Hospital, 75018 Paris, France.
authors.forename: Liliane
authors.initials: L
authors.lastname: Louedec
authors.affiliation: UMR 1018, Inserm-Paris11, CESP, Versailles Saint-Quentin-en-Yvelines University, Paris-Saclay University, Paul Brousse Hospital, 94807 Villejuif, France; Department of Nephrology, Ambroise Paré University Hospital, AP-HP, 92104 Boulogne-Billancourt, France.
authors.forename: Ziad
authors.initials: Z
authors.lastname: Massy
authors.affiliation: Laboratoire EA2496 et Plateforme d'Imagerie du Vivant (PIV), Paris Descartes University, Sorbonne Paris Cité, Montrouge, France.
authors.forename: Jeremy
authors.initials: J
authors.lastname: Sadoine
authors.affiliation: Service d'Explorations Fonctionnelles Multidisciplinaires, AP-HP, Hôpital Tenon, Paris, France; Inserm, UMR S 1155, Hôpital Tenon, Paris, France.
authors.forename: Michel
authors.initials: M
authors.lastname: Daudon
authors.affiliation: Laboratoire EA2496 et Plateforme d'Imagerie du Vivant (PIV), Paris Descartes University, Sorbonne Paris Cité, Montrouge, France.
authors.forename: Catherine
authors.initials: C
authors.lastname: Chaussain
authors.affiliation: CNRS, Laboratoire de Chimie de la Matière Condensée de Paris, UPMC, Collège de France, Paris, France; Laboratoire de Physique des Solides, Université Paris XI, Orsay, France.
authors.forename: Dominique
authors.initials: D
authors.lastname: Bazin
authors.affiliation: UMR 1148, Inserm-Paris7, Denis Diderot University, Xavier Bichat Hospital, 75018 Paris, France.
authors.forename: Jean-Baptiste
authors.initials: JB
authors.lastname: Michel
mesh_terms: D000818:Animals; D001031:Apatites / Q000378:metabolism*; D001158:Arteries / Q000000981:diagnostic imaging / Q000378:metabolism* / Q000648:ultrastructure; D002130:Calcium Phosphates; D000073888:Cell-Free Nucleic Acids / Q000235:genetics / Q000378:metabolism*; D003460:Crystallization; D004247:DNA / Q000235:genetics / Q000378:metabolism*; D004195:Disease Models, Animal; D006801:Humans; D008855:Microscopy, Electron, Scanning; D051381:Rats; D017550:Spectroscopy, Fourier Transform Infrared; D061205:Vascular Calcification / Q000000981:diagnostic imaging / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D055114:X-Ray Microtomography
chemical_list: D001031:Apatites; D002130:Calcium Phosphates; D000073888:Cell-Free Nucleic Acids; D004247:DNA; C020243:calcium phosphate
keywords: Aneurysm; Calcification; Calcium score; Free DNA; Human atherosclerosis; Smooth muscle cell