Chronic Pain Linked to Genetic Changes in Immune System

Researchers are currently working to better understand chronic pain, as it’s difficult to treat and can lead to lifelong disability for some sufferers. According to an NIH study released last year, some 25.3 million American adults have experienced chronic pain every day for the past three months. A study from McGill University revealed in the journal Scientific Reports that chronic pain may change the way genes perform in the immune system. "We found that chronic pain changes the way DNA is marked not only in the brain but also in T cells, a type of white blood cell essential for immunity", says Moshe Szyf, a professor in the Faculty of Medicine at McGill. "Our findings highlight the devastating impact of chronic pain on other important parts of the body such as the immune system." Chronic pain is any pain that persists for six months or longer, and it can have both a physical and emotional impact. The McGill team assessed DNA from brains and white blood cells of rats, using a method that mapped DNA marking by a chemical called a methyl group. "Methyl marks are important for regulating how these genes function," explains co­author Laura Stone, a professor in Dentistry and researcher in the Alan Edwards Centre for Research on Pain. This kind of chemical marking is a part of the growing field of epigenetics, which employs modifications that turn genes “on” or “off”, effectively reprogramming how they perform. "We were surprised by the sheer number of genes that were marked by the chronic pain ­- hundreds to thousands of different genes were changed," said Szyf. "We can now consider the implications that chronic pain might have on other systems in the body that we don't normally associate with pain." More research will be needed, but Szyf and his team are hoping that the study can jumpstart new avenues of treatment for specific genes marked by chronic pain. The findings of the study could open new channels to diagnosing and treating chronic pain in humans, the researchers suggest, as some of the genes discovered to be marked by chronic pain could also represent new targets for pain treatment.