By Paige Richardson
42006794
A new study has shown that child abuse in men can lead to long lasting changes in the brain as it affects a stress-control related gene, even decades after the abuse. Michael Meaney and a team of researchers at McGill University in Montreal, Canada noticed this phenomena after releasing it followed a pattern seen in stressed baby rats. A past study conducted on rats showed that those which suffered maternal neglect also suffered altered workings of the hypothalmic-pituitary-adrenal axis (also known as HPA axis), "a system that secretes particular hormones in response to stress". In the cases of the abused rats, the "regulartory region of a gene of the glucocoticoid receptor" which is responsible for "damping down the HPA response" did not function correctly and resulted in these animals suffering "chronically higher stress levels".
In this more recent study, scientists have discovered the same phenomena in the brains of human beings by conducting a postmortem comparison of the DNA extracted from the hippocampus (an area of the brain where the gene is present) of 12 men who were abused and committed suicide, with two age matched groups: nonabused men who did not commit suicide and nonabused men who died suddenly from other causes. The study showed similarities to the study of the abused rats, as in both cases there were "increases in methylation at a site in the promoter of the gene" only in the brains of those who were abused, making the gene less capable of altering the stress response.
Research like this is vital for our understanding of human genetics as it looks shows that environmental exposures can hinder brain development as they can affect solely gene expression also known as an epigenetic change and cause long-lasting behaviour change. It has been noted for years that children who suffer abuse also are subject to several health issues in years to come. Studies like this may be the beginning of our insight into why this is so.
Resources:
Holden, C., Abuse Leaves Its Mark on the Brain.
http://sciencenow.sciencemag.org/cgi/content/full/2009/223/1
23/02/2009 (accessed 22/03/2009)
