Analysis of G(-174)C IL-6 polymorphism and plasma concentrations of inflammatory markers in patients with type 2 diabetes and peripheral arterial disease
- M Libra1,
- S S Signorelli2,
- Y Bevelacqua1,
- P M Navolanic1,
- V Bevelacqua1,
- J Polesel3,
- R Talamini3,
- F Stivala1,
- M C Mazzarino1,
- G Malaponte1
- 1Department of Biomedical Sciences, University of Catania, Via Androne, 83-95124, Catania, Italy
- 2Department of Internal Medicine, Angiology Unit, University of Catania
- 3Epidemiology Unit, Centro di Riferimento Oncologico, 33081 Aviano, Italy
- Correspondence to: Dr G Malaponte Department of Biomedical Sciences, University of Catania, Via Androne, 83-95124 Catania, Italy;
- Accepted 25 May 2005
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.
- CRP, C reactive protein
- IL-6, interleukin 6
- PAD, peripheral arterial disease
- PCR, polymerase chain reaction
- VEGF, vascular endothelial growth factor
The first two authors contributed equally to this work.