Department of Biomedical Sciences and Technologies, School of Medicine, Università di Udine, Udine, Italy.
BMC Med Genet. 2010 Feb 22;11:29. doi: 10.1186/1471-2350-11-29.
The interleukin-1 (IL-1) family of cytokines is involved in the inflammatory and repair reactions of skeletal muscle during and after exercise. Specifically, plasma levels of the IL-1 receptor antagonist (IL-1ra) increase dramatically after intense exercise, and accumulating evidence points to an effect of genetic polymorphisms on athletic phenotypes. Therefore, the IL-1 family cytokine genes are plausible candidate genes for athleticism. We explored whether IL-1 polymorphisms are associated with athlete status in European subjects.
Genomic DNA was obtained from 205 (53 professional and 152 competitive non-professional) Italian athletes and 458 non-athlete controls. Two diallelic polymorphisms in the IL-1beta gene (IL-1B) at -511 and +3954 positions, and a variable number tandem repeats (VNTR) in intron 2 of the IL-1ra gene (IL-1RN) were assessed.
We found a 2-fold higher frequency of the IL-1RN 1/2 genotype in athletes compared to non-athlete controls (OR = 1.93, 95% CI = 1.37-2.74, 41.0% vs. 26.4%), and a lower frequency of the 1/1 genotype (OR = 0.55, 95% CI = 0.40-0.77, 43.9% vs. 58.5%). Frequency of the IL-1RN 2/2 genotype did not differ between groups. No significant differences between athletes and controls were found for either -511 or +3954 IL-1B polymorphisms. However, the haplotype (-511)C-(+3954)T-(VNTR)2 was 3-fold more frequent in athletes than in non-athletes (OR = 3.02, 95% CI = 1.16-7.87). Interestingly, the IL-1RN 1/2 genotype was more frequent in professional than in non-professional athletes (OR = 1.92, 95% CI = 1.02-3.61, 52.8% vs. 36.8%).
Our study found that variants at the IL-1ra gene associate with athletic status. This confirms the crucial role that cytokine IL-1ra plays in human physical exercise. The VNTR IL-1RN polymorphism may have implications for muscle health, performance, and/or recovery capacities. Further studies are needed to assess these specific issues. As VNTR IL-1RN polymorphism is implicated in several disease conditions, athlete status may constitute a confounding variable that will need to be accounted for when examining associations of this polymorphism with disease risk.
白细胞介素-1（IL-1）家族细胞因子参与运动过程中和运动后的骨骼肌炎症和修复反应。具体来说，剧烈运动后血浆中白细胞介素-1受体拮抗剂（IL-1ra）的水平显著升高，越来越多的证据表明遗传多态性对运动表型有影响。因此，IL-1 家族细胞因子基因是运动能力的候选基因。我们探讨了 IL-1 多态性是否与欧洲受试者的运动员身份有关。
从 205 名（53 名职业运动员和 152 名竞技非职业运动员）意大利运动员和 458 名非运动员对照中获得基因组 DNA。评估了 IL-1beta 基因（IL-1B）的两个二核苷酸多态性（-511 和 +3954 位）和 IL-1ra 基因（IL-1RN）内含子 2 中的可变数串联重复（VNTR）。
我们发现运动员中 IL-1RN 1/2 基因型的频率是对照组的两倍（OR=1.93，95%CI=1.37-2.74，41.0% vs. 26.4%），而 1/1 基因型的频率较低（OR=0.55，95%CI=0.40-0.77，43.9% vs. 58.5%）。两组间 IL-1RN 2/2 基因型的频率无差异。-511 或 +3954 IL-1B 多态性在运动员和对照组之间无显著差异。然而，-511)C-（+3954)T-（VNTR）2 单倍型在运动员中的频率比非运动员高 3 倍（OR=3.02，95%CI=1.16-7.87）。有趣的是，IL-1RN 1/2 基因型在职业运动员中比非职业运动员更常见（OR=1.92，95%CI=1.02-3.61，52.8% vs. 36.8%）。
我们的研究发现，IL-1ra 基因的变异与运动员身份有关。这证实了细胞因子 IL-1ra 在人体运动中的关键作用。VNTR IL-1RN 多态性可能与肌肉健康、表现和/或恢复能力有关。需要进一步的研究来评估这些特定问题。由于 VNTR IL-1RN 多态性与多种疾病有关，因此运动员身份可能是一个混杂因素，在研究该多态性与疾病风险的关联时需要加以考虑。
