Epigenetics Part 2

THE DARK SIDE OF EPIGENETICS…..

Epigenetic modifications in expression of our genome can occur throughout our lifetime, however they are most critical in the early years of life particularly in the embryonic development of the fetus. This is an absolutely critical timepoint as epigenetic modifications here will have life-long effects.¹

Are you wondering how a mother can contribute to the epigenetic modifications in her unborn child based of her own behaviour?

Lets look at a striking example of how vital MATERNAL MENTAL HEALTH is during pregnancy…

A cohort study followed a selection of women who were pregnant in New York at the time of the World Trade Centre terrorist attacks, a portion of these women subsequently developed post-traumatic stress disorder (PTSD). At birth cortisol levels of the infant were collected.  Cortisol is known as ‘the stress hormone’ its levels in the body are controlled by the hypothalamus in the brain. Cortisol has many functions one of which is stimulating ‘anti-stress pathways’ in the body. It was shown that cortisol levels in both the mothers with PTSD and their child were lower than normal. It was hypothesised that stress experienced by the mother during the terrorist attacks and thereafter had caused epigenetic modifications in the development of the fetuses hypothalamus and the adjoining stress pathways. Subsequent research provided further evidence that these children showed greater distress then other children in response to stressful stimuli.^2-4

In the last blog we mentioned that epigenetic modification seems to be preparatory survival modifications for the offspring in later life so you may think, well how would this be an effective survival modification?

Perhaps thousands of years ago there was an advantage for a child to be born more ‘sensitive’ and ‘hypervigilant’, particularly if your village was prone to Sabre Tooth tiger attacks. So the mothers trauma in these cases may confer a survival advantage for her alert offspring. However, for those children growing up in a first world country where danger of this nature is rare it may actually be a deleterious modification to the child’s physiology leading to variety of potential psychological conditions like anxiety disorders .^2-4

In short, stress is a significant factor in affecting fetal development, it is something every mother should attempt to address and minimise IF POSSIBLE!

Potentially modifiable behaviours in developed countries like obesity, alcohol intake and smoking also cause epigenetic changes in their offspring and will be discussed in upcoming blogs. Stay tuned for Epigenetics Part 3 in which we discuss one of the most DEADLY EPIDEMICS of modern times and its impact on fetal development….

References

1.  Rivera RM, Bennett LB. Epigenetics in humans: an overview. Curr Opin Endocrinol Diabetes Obes. 2010 Dec;17(6):493-9.

2.  Yehuda R, Cai G, Golier JA, Sarapas C, Galea S, Ising M, et al. Gene expression patterns associated with posttraumatic stress disorder following exposure to the World Trade Center attacks. Biol Psychiatry. 2009 Oct 1;66(7):708-11.

3.  Yehuda R, Engel SM, Brand SR, Seckl J, Marcus SM, Berkowitz GS. Transgenerational Effects of Posttraumatic Stress Disorder in Babies of Mothers Exposed to the World Trade Center Attacks during Pregnancy. The Journal of Clinical Endocrinology & Metabolism. 2005;90(7):4115-4118.

4.  Karr-Morse R. Scared Sick : The Role of Childhood Trauma in Adult Disease. New York: Basic Books; 2012 [Available