Department of Epidemiology and Biostatistics, School of Public Health, Imperial College London, London, UK; Department of Electron Microscopy / Molecular Pathology, The Cyprus Institute of Neurology and Genetics, Nicosia, Cyprus.
Eur J Clin Invest. 2015 Mar;45(3):303-32. doi: 10.1111/eci.12406.
Following wider acceptance of 'the thrifty phenotype' hypothesis and the convincing evidence that early-life exposures can influence adult health even decades after the exposure, much interest has been placed on the mechanisms through which early-life exposures become biologically embedded.
In this review, we summarize the current literature regarding biological embedding of early-life experiences. To this end, we conducted a literature search to identify studies investigating early-life exposures in relation to DNA methylation changes. In addition, we summarize the challenges faced in investigations of epigenetic effects, stemming from the peculiarities of this emergent and complex field. A proper systematic review and meta-analyses were not feasible given the nature of the evidence.
We identified seven studies on early-life socio-economic circumstances, 10 studies on childhood obesity and six studies on early-life nutrition all relating to DNA methylation changes that met the stipulated inclusion criteria. The pool of evidence gathered, albeit small, favours a role of epigenetics and DNA methylation in biological embedding, but replication of findings, multiple comparison corrections, publication bias and causality are concerns remaining to be addressed in future investigations.
Based on these results, we hypothesize that epigenetics, in particular DNA methylation, is a plausible mechanism through which early-life exposures are biologically embedded. This review describes the current status of the field and acts as a stepping stone for future, better designed investigations on how early-life exposures might become biologically embedded through epigenetic effects.
随着“节俭表型”假说被更广泛接受，以及有说服力的证据表明，即使在暴露几十年后，早期生活经历也会影响成年人的健康，因此，人们对早期生活经历如何在生物学上被嵌入的机制产生了极大的兴趣。
在这篇综述中，我们总结了关于早期生活经历生物学嵌入的现有文献。为此，我们进行了文献检索，以确定研究早期生活暴露与 DNA 甲基化变化之间关系的研究。此外，我们总结了在研究表观遗传效应时面临的挑战，这些挑战源于这一新兴且复杂领域的特殊性。由于证据的性质，我们无法进行适当的系统评价和荟萃分析。
我们确定了七项关于早期社会经济环境的研究、十项关于儿童肥胖的研究和六项关于早期营养的研究，这些研究都与符合规定纳入标准的 DNA 甲基化变化有关。尽管收集的证据数量较少，但这一证据表明，表观遗传学和 DNA 甲基化在生物学嵌入中起作用，但需要进一步研究以复制研究结果、纠正多重比较、解决发表偏倚和因果关系等问题。
基于这些结果，我们假设表观遗传学，特别是 DNA 甲基化，是早期生活经历在生物学上被嵌入的一种合理机制。本综述描述了该领域的现状，为未来更好地设计关于早期生活经历如何通过表观遗传效应在生物学上被嵌入的研究提供了基础。
