Epigenetic Effects of Environment
Gene expression can be affected by the environment through epigenetic mechanisms. Negative environmental influences, such as maternal deprivation, child abuse and stress have been shown to have a profound effect on gene expression, including transgenerational epigenetic effects in which physiological and behavioral (intellectual) transfer of information across generations-not-yet-conceived is effected. In the Överkalix study in Sweden, the effects of epigentic inheritance were shown to have a direct correlation to the environmental influences faced by the parents and grandparents. Many physiological and behavioral characteristics ascribed to Mendelian inheritance are due in fact to transgenerational epigenetic inheritance. The implications in terms of foster care and the cost to society as a whole is that the stress, deprivation and other negative environmental factors many foster children are subjected to has a detrimental effect not only their physical, emotional and cognitive well-being, but that the damage can transcend generations.
In studies of the adult offspring of Holocaust survivors, parental PTSD was a risk factor for the development of PTSD in adult offspring in comparison to those whose parents went through the Holocaust without developing PTSD. The offspring of survivors with PTSD had lower levels of urinary cortisol excretion, salivary cortisol and enhanced plasma cortisol suppression in response to low dose dexamethasone administration than offspring of survivors without PTSD. Low cortisol levels are associated with parental, particularly maternal, PTSD. This is in contrast to the normal stress response in which cortisol levels are elevated after exposure to a stressor. The results of the study point to the involvement of epigenetic mechanisms.
|Epigenetic Effects of Abuse|
"In addition, the effects of abuse may extend beyond the immediate victim into subsequent generations as a consequence of epigenetic effects transmitted directly to offspring and/or behavioral changes in affected individuals. (Neighh GN et al. 2009)
It has been suggested in various studies that the deleterious epigentic effects may be somewhat ameliorated through pharmacological manipulations in adulthood via the administration of nerve growth factor-inducible protein A, and through the inhibition of a class of enzymes known as the histone deacetylases (HDACs). "HDAC inhibitors (HDACIs) such as Trichostatin A (TSA); "TSA can be used to alter gene expression by interfering with the removal of acetyl groups from histones", and L-methionine an essential amino acid, have been developed for the treatment of a variety of malignancies and neurodegenerative disorders. Drug combination approaches have also shown promise for the treatment of mood disorders including bipolar disorder, anxiety and depression."
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