Abstract
Preterm birth (PTB) can be defined as the endpoint of a complex process that could be influenced by maternal and environmental factors. Epigenetics recently emerged as an interesting field of investigation since it represents an important mechanism of regulation. This study evaluates epigenetic impact of preterm birth on DNA methylation. Genome-wide DNAm was measured using the Illumina 450K array in cord blood samples obtained from 72 full term and 18 preterm newborns. Lymphocyte composition was calculated based on specific epigenetic markers that are present on the 450k array. Differential methylation analysis was performed both at site and region level; moreover, stochastic epigenetic mutations (SEMs) were also evaluated. The study showed significant differences in blood cell composition between the two groups. Moreover, after multiple testing correction, statistically significant differences in DNA methylation levels emerged between the two groups both at site and region levels. Results obtained were compared to those reported by previous EWAS, leading to a list of more consistent genes associated with PTB. Finally, the SEMs analysis revealed that the burden of SEMs resulted significantly higher in the preterm group. In conclusion, PTB resulted associated to specific epigenetic signatures that involve immune system. Moreover, SEMs analysis revealed an increased epigenetic drift at birth in the preterm group.
Highlights
Preterm birth (PTB) is defined as birth before 37 weeks of pregnancy
An innovative analysis able to identify stochastic epigenetic mutations (SEMs) has been adopted in order to have an estimation of SEMs burden at birth in PTB babies
A significant difference between preterm and full-term babies emerged considering the weight at birth, the type of delivery (Eutocic delivery or not) and the duration of pregnancy
Summary
Preterm birth (PTB) is defined as birth before 37 weeks of pregnancy. According to the World Health Organization the prevalence of PTB is estimated to be in a range from 5% to 18% in singleton pregnancies [1]. Preterm birth is considered a leading cause of perinatal mortality and long-term morbidity and it is a well-known risk factor for many complex diseases occurring during adult age. Several studies analyzed cord blood DNA methylation levels comparing preterm and full-term babies and reported a great number of significant differences even if the consistence among these studies has not been evaluated yet [11,12,13,14,15]. Considering the strong background regarding a potential role of epigenetics in PTB, the aim of the present study was to investigate DNA methylation differences associated with PTB at genome wide level and to evaluate consistency of results published so far. SEMs have been recently defined as a biomarker of epigenetic drift and of exposure-related accumulation of DNA damage [16] and might have a role in long term effects of PTB
Sign-in/Register to view highlights & summary 
Published Version (
Free)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call