A new “twin” study conducted in the UK shows that a person’s experience in life may affect pain tolerance.
The study was conducted using 50 identical twins and by looking at the genes and gene expression. Identical twins share 100% of their genes and are therefore often used in studies to compare the “expression” of these genes.
The study of gene expression, known as “epigenetics”, involves looking at how environmental factors affect the way in which a person’s genes are used (expressed). The UK study, conducted at the King’s College in London, was able to demonstrate that environmental factors contribute to the sensitivity in pain genes, in particularly, gene TRPA1.
The study used DNA technology known as MeDIP sequencing (Methylated DNA immunoprecipitation) to look at the molecular mechanisms involved in genome-wide DNA methylation. The gene expression of the 25 sets of identical twins was compared to 50 non-twins. The methylation of certain genes is an important step in the expression of that gene. It was found that if methylation had occurred on a “pain” genome on one identical twin but not the other, and this methylation was associated with increased pain sensitivity from the “heat” test, it was postulated based on the theory of epigenetics that an environmental factor had contributed to the sensitisation of that individual twin to pain.
Chronic pain sufferers may find new relief in the future
This new exciting discovery in biomedical engineering brings about the possibility that a new drug may be developed to help chronic pain sufferers. Although the study tested acute pain tolerance, by applying a heat probe on to the arm of each twin and gently increasing the heat until pain was reported, acute pain tolerance is an indicator for risk of chronic pain.
It is possible that in the future a drug may be developed to help “turn off” the epigenetic influence on pain gene expression. This discovery gives new hope to the millions of chronic pain sufferers world-wide.
Bell et all. 2014. Differential methylation of the TRPA1 promoter in pain sensitivity. Nature Communications, online. http://www.nature.com/ncomms/2014/140204/ncomms3978/full/ncomms3978.html
Kings College Press release. 4 Feb 2014. http://www.kcl.ac.uk/newsevents/news/newsrecords/2014/February/Pain-sensitivity-may-be-influenced-by-lifestyle-and-environment.aspx