The way a baby is delivered may epigenetically impact stem cells of the infant, according to a new study at Karolinska Institutet. Their findings could help scientists understand the differences between various modes of delivery, for example, why babies delivered via cesarean section are statistically more susceptible to immunological diseases. It’s still uncertain whether this epigenetic mechanism is long-term or temporary.
Women are now more than ever electing to give birth by cesarean section, the most popular surgical procedure in fertile women. However, there seems to be increased risk of developing diseases for babies delivered this way, such as asthma, type 1-diabetes, obesity, and celiac disease. The explanation for these associations is not yet clear.
“The biological mechanisms predisposing a fetus or a newborn infant to get a certain disease later in life are complex and depend on both genetic and environmental factors during formative years”, explains Tomas Ekström, Professor of Molecular Cell Biology. “In this study, our focus has been whether the way a baby is born can have an impact on a cellular level in the form of epigenetic alterations in DNA.”
In their recent study published in American Journal of Obstetrics and Gynecology, researchers used sorted cord blood to examine epigenetic differences in stem cells. They analyzed the global DNA methylation of the hematopoietic stem cells in a total of 43 infants (33 boys), including 18 infants delivered by elective cesarean section. They then performed genome-wide, locus-specific DNA methylation analysis on 12 infants, of whom 6 were delivered by cesarean section. They found significant differences in the epigenetic markup between groups in almost 350 DNA regions, including some genes thought to be involved in metabolism and immune defense.
“During a vaginal delivery, the fetus is exposed to an increased level of stress, which in a positive way will prepare the unborn baby for life outside the uterus,” says Mikael Norman, a pediatrician and Professor of Neonatology. “This activation of the fetus’ defense systems doesn’t occur when a cesarean section is performed before labor begins, which in turn could be a possible cause for the noticed differences between the groups.”
This valuable new research adds important knowledge to the current understanding of the impact of mode of delivery, particularly cesarean section, on gene expression in blood stem cells. It may also shed some light on the immune system’s involvement in health and disease later in life. However, this study did not determine if the epigenetic effects were persistent over time and more research should be conducted to determine how epigenetic changes might affect disease risk in the long-term.
Source: Learn all about it and read more about their findings here: Cesarean delivery and hematopoietic stem cell epigenetics in the newborn infant: implications for future health? Malin Almgren, Titus Schlinzig, David Gomez-Cabrero, Agneta Gunnar, Mikael Sundin, Stefan Johansson, Mikael Norman & Tomas J. Ekström.
References: Medical Xpress. Caesarian section may cause epigenetic changes. July 2014.