Poulsen P, Vaag A
Diabetes Research Center, Odense University Hospital, Odense, Denmark.
Twin Res. 2001 Oct;4(5):350-5. doi: 10.1375/1369052012515.
Several epidemiological and metabolic studies have demonstrated an impact of the intrauterine environment on the development of disease in adult life, including Type 2 diabetes and glucose intolerance. Our finding of lower birth weights among monozygotic diabetic twins compared to their non-diabetic genetically identical co-twins confirms this association and, furthermore, eliminates the possibility that the association could be explained solely by common genes leading to both impaired intrauterine growth and increased risk of Type 2 diabetes. Due to an often shared placenta monozygotic twins may experience a more adverse intrauterine environment compared to dizygotic twins and may therefore be more prone to develop various metabolic abnormalities. Our findings of a higher glucose and insulin profile after oral glucose ingestion, and recently lower insulin-stimulated glucose uptake--indicating glucose intolerance and insulin resistance--among monozygotic compared to dizygotic twins may to some extent question the validity of classical twin studies in diabetes research where equal environmental influences in monozygotic and dizygotic twins is assumed. The potential role of an adverse intrauterine environment in causing Type 2 diabetes in humans, may to some degree alter our conception of the twin model in diabetes research including the interpretation of aetiological conclusions reached in previous classical twin studies of diabetes. However, our present knowledge is far too insufficient to discard the results from classical twin studies concerning the relative role of genes versus environment for the development of diabetes and its metabolic effects.
多项流行病学和代谢研究表明，子宫内环境对成年后疾病的发展有影响，包括2型糖尿病和葡萄糖耐量异常。我们发现，同卵双胞胎糖尿病患者的出生体重低于其非糖尿病的同基因双胞胎，这证实了这种关联，此外，排除了这种关联可能仅由导致子宫内生长受损和2型糖尿病风险增加的共同基因来解释的可能性。由于同卵双胞胎通常共享一个胎盘，与异卵双胞胎相比，他们可能经历更不利的子宫内环境，因此可能更容易出现各种代谢异常。我们发现，与异卵双胞胎相比，同卵双胞胎口服葡萄糖后血糖和胰岛素水平更高，最近还发现胰岛素刺激的葡萄糖摄取更低（表明葡萄糖耐量异常和胰岛素抵抗），这在一定程度上可能会质疑经典双胞胎研究在糖尿病研究中的有效性，因为经典双胞胎研究假设同卵双胞胎和异卵双胞胎受到的环境影响相同。子宫内不良环境在导致人类2型糖尿病中的潜在作用，可能在某种程度上改变我们在糖尿病研究中对双胞胎模型的认识，包括对先前经典双胞胎糖尿病研究得出的病因学结论的解释。然而，我们目前的知识远远不足以摒弃经典双胞胎研究关于基因与环境在糖尿病发展及其代谢影响方面相对作用的结果。
