title: Involvement of tissue bacteria in the onset of diabetes in humans: evidence for a concept.
abstract: OBJECTIVE
  Evidence suggests that bacterial components in blood could play an early role in events leading to diabetes. To test this hypothesis, we studied the capacity of a broadly specific bacterial marker (16S rDNA) to predict the onset of diabetes and obesity in a general population.
  
  
  METHODS
  Data from an Epidemiological Study on the Insulin Resistance Syndrome (D.E.S.I.R.) is a longitudinal study with the primary aim of describing the history of the metabolic syndrome. The 16S rDNA concentration was measured in blood at baseline and its relationship with incident diabetes and obesity over 9 years of follow-up was assessed. In addition, in a nested case-control study in which participants later developed diabetes, bacterial phylotypes present in blood were identified by pyrosequencing of the overall 16S rDNA gene content.
  
  
  RESULTS
  We analysed 3,280 participants without diabetes or obesity at baseline. The 16S rDNA concentration was higher in those destined to have diabetes. No difference was observed regarding obesity. However, the 16S rDNA concentration was higher in those who had abdominal adiposity at the end of follow-up. The adjusted OR (95% CIs) for incident diabetes and for abdominal adiposity were 1.35 (1.11, 1.60), p = 0.002 and 1.18 (1.03, 1.34), p = 0.01, respectively. Moreover, pyrosequencing analyses showed that participants destined to have diabetes and the controls shared a core blood microbiota, mostly composed of the Proteobacteria phylum (85-90%).
  
  
  CONCLUSIONS
  16S rDNA was shown to be an independent marker of the risk of diabetes. These findings are evidence for the concept that tissue bacteria are involved in the onset of diabetes in humans.
authors: Inserm U1027, University Paul Sabatier, CHU, Hôpital Rangueil, Avenue Jean Pouhles, Toulouse, France. amar.j@chu-toulouse.fr
authors: J
authors: J
authors: Amar
authors: M
authors: M
authors: Serino
authors: C
authors: C
authors: Lange
authors: C
authors: C
authors: Chabo
authors: J
authors: J
authors: Iacovoni
authors: S
authors: S
authors: Mondot
authors: P
authors: P
authors: Lepage
authors: C
authors: C
authors: Klopp
authors: J
authors: J
authors: Mariette
authors: O
authors: O
authors: Bouchez
authors: L
authors: L
authors: Perez
authors: M
authors: M
authors: Courtney
authors: M
authors: M
authors: Marre
authors: P
authors: P
authors: Klopp
authors: O
authors: O
authors: Lantieri
authors: J
authors: J
authors: Doré
authors: M  A
authors: M
authors: Charles
authors: B
authors: B
authors: Balkau
authors: R
authors: R
authors: Burcelin
mesh_terms: D000328:Adult; D000368:Aged; D001419:Bacteria / Q000145:classification / Q000302:isolation & purification; D015415:Biomarkers / Q000097:blood*; D016022:Case-Control Studies; D003924:Diabetes Mellitus, Type 2 / Q000097:blood* / Q000453:epidemiology / Q000382:microbiology*; D005260:Female; D005602:France; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D024821:Metabolic Syndrome / Q000097:blood*; D054892:Metagenome; D008875:Middle Aged; D009765:Obesity / Q000097:blood; D056128:Obesity, Abdominal / Q000097:blood / Q000453:epidemiology; D012336:RNA, Ribosomal, 16S / Q000097:blood*
chemical_list: D015415:Biomarkers; D012336:RNA, Ribosomal, 16S