Pain sensitivity may be alterable

Date: Feb-05-2014Chronic pain affects people all over the world, yet the underlying molecular

mechanisms that govern it are not well understood. Now, a new UK study of twins finds that

people's sensitivity to pain may be altered by changes in lifestyle and environment through

life.

Individuals who are more sensitive to pain are at higher risk of developing chronic pain.

The discovery lies in a relatively new field of investigation called epigenetics, where

scientists study how genes are switched on and off in response to changes in the body.

The study, led by Dr. Jordana Bell, of the Department of Twin Research & Genetic Epidemiology

at King's College London, and published in Nature Communications, is the first to find

that pain sensitivity may not be as inflexible as previously thought.

The findings raise the possibility that pain sensitivity might be treatable by drugs that

switch certain genes off.

Identical twins' genes differ epigenetically

Unlike non-identical twins, who on average share only 50% of their genes, identical twins

share 100%. So it follows that any differences in gene expression must result from processes

that act on those genes, such as epigenetics, which can come through differences in environment

and lifestyles. This makes identical twins ideal subjects for studying the effects of

epigenetics.

For this study, the researchers recruited 25 pairs of identical twins and tested their

sensitivity to pain by applying a heat probe to an arm on each twin.

They asked the participants to press a button when the heat became painful - this established

their pain threshold.

Then, by sequencing the DNA obtained from participants' blood samples, the researchers

pinpointed 5.2 million locations where epigenetic changes had occurred across the whole genome

and compared them with those of 50 unrelated individuals.

By doing this, they could identify which parts of the genome carried epigenetic changes

differentially associated with high and low pain sensitivity.

The team found epigenetic modifications in nine genes related to pain sensitivity that were

different between individual twins in a pair.

Epigenetic change is a 'dimmer switch' for gene expression

One of the study's corresponding authors, Tim Spector, professor of Genetic Epidemiology at

King's College London, says:

"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."

One gene in particular, TRPA1, which is already known to be involved with pain sensitivity

and a target in the development of analgesics or painkillers, showed the most epigenetic

changes.

However, although TRPA1 is already known to be involved with pain sensitivity, this is the

first time that pain sensitivity has been linked to epigenetic changes in the gene.

Finding opens possibility of drugs that work epigenetically to change pain sensitivity

The finding is important because it suggests it may be possible to switch the gene on and off

with drugs and thereby change a person's pain sensitivity.

This could help people with chronic pain, Dr. Bell says:

"The potential to epigenetically regulate the behaviour 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."

Meanhwile, Medical News Today recently reported a study where a team of researchers

in the US found that people's sensitivity to pain is linked to brain structure

differences.

Written by Catharine Paddock PhD




View all articles written by Catharine, or follow Catharine on:




Copyright: Medical News Today

Not to be reproduced without the permission of Medical News Today.

Courtesy: Medical News Today Note: Any medical information available in this news section is not intended as a substitute for informed medical advice and you should not take any action before consulting with a health care professional.