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J Clin Pathol 59:211-215 doi:10.1136/jcp.2004.025452
  • Original article

Analysis of G(-174)C IL-6 polymorphism and plasma concentrations of inflammatory markers in patients with type 2 diabetes and peripheral arterial disease

  1. M Libra1,
  2. S S Signorelli2,
  3. Y Bevelacqua1,
  4. P M Navolanic1,
  5. V Bevelacqua1,
  6. J Polesel3,
  7. R Talamini3,
  8. F Stivala1,
  9. M C Mazzarino1,
  10. G Malaponte1
  1. 1Department of Biomedical Sciences, University of Catania, Via Androne, 83-95124, Catania, Italy
  2. 2Department of Internal Medicine, Angiology Unit, University of Catania
  3. 3Epidemiology Unit, Centro di Riferimento Oncologico, 33081 Aviano, Italy
  1. Correspondence to:
 Dr G Malaponte
 Department of Biomedical Sciences, University of Catania, Via Androne, 83-95124 Catania, Italy; g.malaponte{at}unict.it
  • Accepted 25 May 2005

Abstract

Aims: To determine whether the G(−174)C interleukin 6 (IL-6) polymorphism influences the development of peripheral arterial disease (PAD) in individuals with type 2 diabetes. This was investigated by comparing the distribution of G(−174)C genotypes between patients with type 2 diabetes and PAD (PAD+) and those with type 2 diabetes but without PAD (PAD). Plasma concentrations of IL-6, fibrinogen, C reactive protein (CRP), and vascular endothelial growth factor (VEGF) were also compared in PAD+ and PAD patients.

Methods: Blood samples were collected from 146 PAD+ and 144 PAD patients. SfaNI was used to determine the G(−174)C genotype. Plasma concentrations of IL-6, fibrinogen, CRP, and VEGF were measured by an enzyme linked immunosorbent assay.

Results: The GG genotype was more common in PAD+ patients than in PAD patients. PAD+ patients also had increased mean plasma concentrations of IL-6, fibrinogen, CRP, and VEGF compared with PAD patients. Mean plasma concentrations of IL-6, fibrinogen, and CRP in both PAD+ and PAD patients were higher in those with the GG genotype than in those with the GC or CC genotypes. In contrast, mean plasma concentrations of VEGF in PAD+ and PAD patients were not significantly different between those with different G(−174)C genotypes.

Conclusions: These results support a model in which the GG genotype promotes PAD development among individuals with type 2 diabetes by inducing increased release of IL-6. Higher concentrations of IL-6 among those with the GG genotype is associated with increased plasma concentrations of fibrinogen and CRP.

Footnotes

  • The first two authors contributed equally to this work.