Impact of cytokine gene polymorphism on cardiovascular risk in renal transplant recipients

Cardiovascular events are the leading causes of morbidity and mortality in renal transplant recipients (RTR). Given the role of inflammation in atherosclerosis, the contribution of functional polymorphisms of cytokines to cardiovascular diseases (CVD) was assessed in RTR in this study. Polymorphisms of tumour necrosis factor alpha (TNF-α) gene [-308 (G → A), -238 (G → A)], interleukin-10 (IL-10) gene [-1082(A → G), -819 (T → C), -592 (A → C)], transforming growth factor beta 1 (TGF-β1) gene [codon 10 (T → C), codon 25 (G → C)], carotis intima media thickness (CIMT), left ventricular mass index (LVMI), 24-h ambulatory blood pressure and serum lipoprotein homocysteine level, erythrocyte sedimentation rate, serum C-reactive protein (CRP) and serum fibrinogen level of RTR were determined. Seventy-two RTR (26 cadaveric allograft, 46 living-related allograft, 43 male, 29 female) were included in this study. LVMI were similar in TNF-α, IL-10 and TGF-βl genotypes. Right and left CIMT were higher in TT genotype (n = 16) than CT (n = 46) and CC (n = 10) genotypes of TGF-β1 codon 10 (T → C) gene polymorphism (RCIMT, 7.7 ± 2.2 mm vs. 7.0 ± 1.4 mm vs. 5.9 ± 1.4 mm, P = 0.025; LCIMT, 8.5 ± 2.5 mm vs. 7.0 ± 1.3 mm vs. 6.1 ± 1.2 mm, P = 0.002). Lipoprotein (a) level of TT genotype (35.5 ± 22.5 mg/dl) was higher than CC (4.1 ± 2.8 mg/dl) and CT (20.4 ± 11.2 mg/dl) genotypes of TGF-βl codon 10 (T → C) gene polymorphism (P = 0.037). High producers of cytokine IL-10 -1082 [GG (n = 22) vs. AA + AG (n = 50)] and low producers of TGF-β codon 25 [GC + CC (n = 17) vs. GG (n = 55)] had lower IMT of carotid artery but the difference did not reach statistical significance (P > 0.05). The CIMT of renal transplant patients was similar in IL-10 (-819, -592) and TNF-α (-308, -238) genotypes. No difference was observed in 24-h ambulatory blood pressure levels, serum lipoproteins, plasma homocysteine level, erythrocyte sedimentation rate, serum CRP, serum fibrinogen level in IL-10, TNF-α and TGF-β1 genotypes. Besides the well-known factors, TGF-β1 gene polymorphisms might play a role in CVD in RTR even at early stages of asymptomatic atherosclerosis.