Archive for May, 2010

Gene Modifications and Post-Traumatic Stress Disorder

Neuroscientists and others who study human behavior ask an interesting variation of the old question “which came first, the chicken or the egg?”  In the case of humans, the question comes down to “Do the biochemical changes produce the behavior or does the behavior produce the biochemical changes?”  Recent research tries to deal with aspects of this troublesome question.

Research from Columbia University shows that specific genes can be altered as a result of traumatic events.  The study found in persons with post-traumatic stress disorder (PTSD) that certain genes involved in immune response and other genes that are linked to brain cell development have different levels of modification than genes from a non-affected population.  Both sets of genes had changes in the number of methyl groups attached to the genes.  All genes have a certain number of methyl groups connected to them, with these groups functioning to regulate the gene activity.  Addition of more methyl groups to a gene will slow it down or turn it off, decreasing the amount of protein made by that gene.  Decreasing the number of methyl groups leads to an enhancement of gene activity, causing more protein to be produced.

The research team was led by Sandro Galea, a Columbia University physician and epidemiologist.  The team found that individuals with PTSD had significantly lower levels of methylation on genes associated with the immune system, resulting in a higher level of immune response.  The findings could contribute to a better understanding of PTSD.  These individuals have a much higher risk of physical health problems such as heart disease and diabetes.  Details of the research can be found in the May 3 on-line issue of Proceedings of the National Academy of Sciences.

The research team felt that the traumatic experiences leading to PTSD could alter immune function in these individuals.  There are some well-known links between immune function and emotional behavior (we’ll explore some of these in the future).  Decreased activity of genes associated with brain development was observed, but not discussed to any great extent.  But this research could provide useful clues to causes for the increase in physical health problems associated with PTSD

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