All of us know someone who suffers from some degree of persistent pain, and it may even be you. It is a rather common condition, and can be the result of a sports injury, diseases such as arthritis, and even the aging process.
We also know that sometimes, treatment options are limited, with doctors having few remedies for the pain, such as pain killers, heat therapy or attendance at pain clinics. And while these therapies will work for the short-term, chronic pain is real, and sometimes difficult to treat.
Researchers from King’s College searched for the reason why our nervous system sometimes becomes overly sensitive, especially when the injury or disease that caused the nervous system to respond in the first place had healed. Their research led them to study immune cells in the nervous system of mice.
Immune cells have turned out to be important in persistent pain because the team discovered that nerve damage changes epigenetic marks in some of the genes in the immune cells. All cells in our body contain the same RNA. Epigenetic marks silence some of the gene sequences and activate others,
Some epigenetic marks can have direct functional consequences while others just act as primers for future gene changes. The immune cells examined by the researchers behaved normally, but the findings of the epigenetic marks may mean that the cells now had a “memory” of the initial injury.
Science Codex reports that Dr. Franziska Denk, first author of the study, from the Wolfson Centre for Age-Related Diseases at the Institute of Psychiatry, Psychology & Neuroscience (IoPPN), King’s College London, said: ‘We are ultimately trying to reveal why pain can turn into a chronic condition. We already knew that chronic pain patients have nerves that are more active, and we think this is probably due to various proteins and channels in those nerves having different properties.”
What is particularly interesting is that the epigenetic marks remained, even after going through “cell housekeeping,” where most of the cells are replaced and renewed every three weeks or months. Dr. Denk says the big question to be answered is: “Why do crucial proteins keep being replaced by malfunctioning versions of themselves?”
An even bigger issue is to find out if these molecular footprints affect the function of proteins, and if so, is this the reason that chronic pain persists in patients after the initial injury or disease is over. King’s College researchers agree that more investigation is needed, saying, ‘The clues from this study, suggesting epigenetic changes may be involved in pain persisting.” Further studies “will hopefully lead us to better understand the mechanisms underlying chronic pain.”
This interesting study, “Persistent Alterations in Microglial Enhancers in a Model of Chronic Pain,” was published on May 13, 2016, in the journal Cell Reports.