Pain Sensitivity Linked to Lifestyle and Environment

Pain sensitivity can change as certain genes are switched on and off by lifestyle and environmental factors, researchers discovered. The results of their study have huge implications for the future of pain treatment, as pain sensitivity was generally considered to be inflexible.

The study, published Tuesday in Nature Communications, tested 25 pairs of identical twins to examine pain's susceptibility to epigenetics, which chemically alters the expression of a gene by switching it on or off. After determining the participants' pain threshold with a heat probe on their arm, researchers used DNA sequencing to compare epigenetic markers between the twins' genomes to test for differences. The results were then tested against markers of a control group of unrelated individuals for verification.

The study was able to identify nine genes involved in pain that had changed in one twin but not the other over their lifetimes. These changes were most significant in the known pain sensitivity gene TRPA1, already a target of painkillers.

This is the first time TRPA1 has been shown to have the ability to be turned on or off epigentically.

"The potential to epigenetically regulate the behavior of TRPA1 and other genes involved in pain sensitivity is very exciting and could lead to a more effective pain relief treatment for patients suffering with chronic pain," said lead author Jordana Bell from the Department of Twin Research and Genetic Epidemiology at King's College London in a statement Sunday.

Establishing an epigenetic process for reducing pain sensitivity could lead to major advances in the treatment of chronic pain, which is well established to be influenced by a person's sensitivity to everyday pain.

Tim Spector, Professor of Genetic Epidemiology at King's College London, said Sunday, "Epigenetic switching is like a dimmer switch for gene expression. This landmark study shows how identical twins, when combined with the latest technology to look at millions of epigenetic signals, can be used to find the small chemical switches in our genes that make us all unique - and in this case respond to pain differently.'

These differences might hold the key to the future of pain treatment.