Cells Can Remember Injury, Which May Reveal Why Chronic Pain Persists

Cells Can Remember Injury, Which May Reveal Why Chronic Pain Persists

By Staff

A new study from King’s College London offers clues as to why chronic pain can persist, even when the injury that caused it has gone. Although still in its infancy, this research could explain how small injuries leave molecular ‘footprints’ that add up to lasting damage, and ultimately chronic pain.

While chronic pain can have many different causes, the outcome is often the same – an overly sensitive nervous system which responds much more than it should. The question is, why does the nervous system remain in a sensitive state for long periods of time even when the underlying injury or disease is gone?

Researchers from King’s College examined immune cells in the nervous system of mice, which are known to be important for the generation of persistent pain.

In a study published in Cell Reports, they found that nerve damage changes epigenetic marks on some of the genes in these immune cells. Epigenetics is the process that determines which gene is expressed and where. Some epigenetic signals have direct functional consequences, while others are just flags that indicate a potential to act or be modified.

The cells examined in the King’s College study still behaved as normal, but the existence of these novel epigenetic marks may mean that they carry a ‘memory’ of the initial injury.

‘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,” said 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,

“However, it is unclear why these nerves should remain in this overactive, highly sensitive state, even when the initial injury or disease has gone: the back pain from two years ago that never quite went away or the joints that are still painful despite your rheumatoid arthritis being in remission,’ she added.

‘We want to know why these proteins and channels should maintain their altered function over such a long period of time. Cells have housekeeping systems by which the majority of their content are replaced and renewed every few weeks and months - so why do crucial proteins keep being replaced by malfunctioning versions of themselves? Our study is the very first step towards trying to answer this question by exploring the possibility that changes in chronic pain may persist because of epigenetics. We hope that future research in this area could help in the search for novel therapeutic targets,’ she explained.

“This research raises many interesting questions: do neurons also acquire epigenetic footprints as a result of nerve injury? Do these molecular footprints affect the function of proteins? And are they ultimately the reason that chronic pain persists in patients over such long periods of time?” said Professor Stephen McMahon from the IoPPN at King’s College London,

‘The last question is particularly hard to answer, because to study epigenetics we need access to pure cell populations. Obviously, many of these are only accessible in postmortem tissue. However, colleagues at King’s are already doing this in psychiatry, through studies such as The PsychENCODE project, so it is possible,” he added.

“People develop chronic pain for a huge variety of reasons. We therefore need an equally diverse range of treatments to tackle the different root causes. The clues from this study, suggesting epigenetic changes may be involved in pain persisting, will hopefully lead us to better understand the mechanisms underlying chronic pain,” said Dr Giovanna Lalli, Neuroscience & Mental Health Senior Portfolio Developer at the Wellcome Trust, which part-funded the study.

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Authored by: Staff

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Sophie Pesant

@Martha Arntson

Can you tell me who is this chiropractor ??


From a chiropractor!

joan hamm

No way can acunpture help Rsd. The tiny needles that would go into my body would touch nerves. If I get a splinter in my finger or anywhere hurts 10 times more than one without Rsd. Bad pain,!!! If dry skin cracks in winter the pain is horrible. I wish they would work. Rsd attacks areas of wounds. Exercise helps but only a little but does not stop a bad attacks. It’s just while I am cleaning exercising the pain is delayed then my body gets sick weak telling me to get to bed. Meds are the only thing that has kept me alive for six years or I would have to call 911 every day. The attacks come exercise just delays the attack. Sometimes I’m bed ridden for days if I overdo things. I believe your scientists should look in a different direction. But I do see what you discovered with cells but meds are a must or I won’t survive the pain getting worse and worse. Rsd varies with people but if it’s real Rsd this is the truth! Fibromalgia may be what you are concentrating more??? God bless the scientists but they cannot say the cells control the disease if I read it right. Thank you scientists!!! You do need more funding to get better answers. You may get these diseases yourself and then see how somehow the nerves need correcting other than Ketamine. I had four Ketamine shots in spine… I was in bliss for 2 minutes….45 minutes….10 minutes and about 1 minute. I didn’t get help fast enough due to 4 Doctors must say you have it and one must complete the severe painful test Electromyogram… Then one can get Ketamine shots.. So it was too late. If someone is in bad pain all this should be rushed right away instead of waiting five months for answers. Ketamine shots should be immediate then if it works…one has the answer and may be saved.!!!


Great article! I was seeing a Chiropractor who is trained in Epigenetics and now runs his own office doing nothing but teaching as well as treating patients with chronic pain, whether it be from a long ago injury, healed, or a new one. He also does the DNA testing as well as other methods to uncover the real cause of the pain. I strongly suggest that Pain Management Doctors look more closely into this type of treatment. I just happened upon my Epigenetic Doctor via my Pain Management Facility where he was supposed to do the chiropractic as well as acupuncture for my low back and neck pain. It was a fantastic journey, learning how to use this method, along with the medications I was prescribed to keep my pain at a manageable level. I also learned how to heal my leaky gut through his teaching.


That’s an excellent point, Jean - I like it too. “Chronic” does just have a bad sound. I never thought about it, and probably would not have even picked up on the use of the word persistent instead in this article - thanks!

joan hamm

I was abused by a Doctor performing the necessary test Electromyogram. Each electric needle he put every inch of my foot and right calve I screamed the loudest screams in my life. He never once comforted me or asked if he should stop. I was told by Drs. I HAD to have this test if I wanted to know I had RSD. So I pulled my inner strength and allowed him to put so many needles in me. I almost passed out. Then he put one in my groin.!! I asked why . I had no pain in groin area. While the needle was in he told me to bend my body towards the needle. When I did I screamed so loud I thought my voice was gone. I told him STOP STOP STOP and ready to pass out. He said to me if I want test completed I had to let him continue in groin area. I said STOP!!!!! Why would He torture me with every inch of my foot and ankle and calve????? I jumped off table opened the door feeling faint and pain and there were at least Five females of his staff ears against the door as if they were getting ready to rescue me. They saw my white face and said are you okay??? I just wanted out of there. I knew The Dr. Abused me so did his staff. His staff did not want me to leave…they were concerned. My family Dr. Said the results of the test were inconclusive. I told my Dr. That the Dr. Finished the test and wanted to needle me in groin and tummy. I wish I would have sued this Quack but innocent good people don’t think evil ways.so it remains a nightmare in my mind of what is pain people go through for help. He enjoyed my suffering.. I saw it in his face but I needed that test done!!!! Too much a victim we put trust in Drs.

Jean Price

I like the terminology of persistent pain…or life limiting pain, rather than chronic. Chronic has a negative connotation…malingering, complaining…and I believe we need to change this when we speak of lasting or long term pain! There are already enough stigmas surrounding pain, the people who have it, and the confusion of treatment medication versus addiction and illegal drug use. We would do well to be more sensitive to how we describe our pain and ourselves.


Do you know of any Dr who will treat RSD/CRPS patients for pain meds / treatments in our area?
Little River South Carolina
Our son could no longer support himself as he could no longer work- he now lives with us in SC
Can you help?

joan hamm

I have RSD.CRPS nerve damage. I mentally rarely think about or dwell on how I got this disease. I am positive and five times a day I start getting the severe attacks. I never know when or never wait for the attacks. They just happen even when I am having fun never thinking of my disease. So I do not create the pain attacks. I think maybe the attack won’t come ever again and go on with my life. Then Bam there it comes. There are so many symptoms of this disease. One never knows. Without meds I believe I would not be alive six years ago.

Cathy M

Thanks for giving us info on this important new study, and also thanks for letting us know there are scientists taking this seriously, understanding that we pain sufferers aren’t “wimps” or psychologically damaged. So many illnesses were thought to be “all in the mind” before they found the chemical or neural mechanisms! I hope they find the key to chronic pain soon!

Sheryl Donnell

What a fantastic study! This is something every patient with CRPS already knows, but studies like this are crucial for finding cures and better treatments. Outstanding!


Medical researchers lack the ability to connect all the dots when it comes to chronic pain. Researchers are overconfident and unwilling to try very different process of researchThey and us make too much out of their findings and efforts because of wishful thinking. The simple truth is that chronic pain easily outsmarts us and our best researchers. Its time to acknowledge such and develop much different ways of approaching pain- and hopefully we’ll get lucky.
This research is similar to the PKM zeta research- and that has gone nowhere.