Negative Thoughts About Sleep Make Pain Worse

By Pat Anson, Editor

Negative thoughts about pain and not being able to sleep can worsen chronic pain conditions like fibromyalgia, arthritis and back pain, according to British researchers.

“Pain-related sleep beliefs appear to be an integral part of chronic pain patients' insomnia experience,” said Nicole Tang, a psychologist in the Sleep and Pain Laboratory at the University of Warwick. "Thoughts can have a direct and/or indirect impact on our emotion, behaviour and even physiology. The way how we think about sleep and its interaction with pain can influence the way how we cope with pain and manage sleeplessness.”

Tang and her colleagues developed a scale to measure beliefs about sleep and pain in chronic pain patients, along with the quality of their sleep.

The scale was tested on four groups of patients suffering from long-term pain and bad sleeping patterns, and found to be a reliable predictor of future pain and insomnia.

"This scale provides a useful clinical tool to assess and monitor treatment progress during these therapies," said Esther Afolalu, a graduate student and researcher at the University of Warwick. 

university of warwick

"Current psychological treatments for chronic pain have mostly focused on pain management and a lesser emphasis on sleep but there is a recent interest in developing therapies to tackle both pain and sleep problems simultaneously."

Researchers found that people who believe they won't be able to sleep because of their pain are more likely to suffer from insomnia, thus causing more pain. The vicious cycle of pain and sleeping problems was significantly reduced after patients received instructions in cognitive-behavioural therapy (CBT), a form of psychotherapy in which a therapist works with a patient to reduce unhelpful thinking and behavior.

The study, published in the Journal of Clinical Sleep Medicine, is not the first to explore the connection between pain and poor sleep.

A 2015 study published in the journal PAIN linked insomnia and impaired sleep to reduced pain tolerance in a large sample of over 10,000 adults in Norway. Those who had trouble sleeping at least once a week had a 52% lower pain tolerance, while those who reported insomnia once a month had a 24% lower tolerance for pain.

Study Finds Link Between Weather and Chronic Pain

By Pat Anson, Editor

There may be something to the old adage about “feeling under the weather.”

Early results from a smartphone-based weather study in the UK show that rain and lack of sunshine have an impact on how we perceive pain.

Over 9,000 people are participating in The University of Manchester’s Cloudy with a Chance of Pain project,  using a special app to record their daily pain levels.  

The app also captures hourly weather conditions using the phone’s GPS, giving researchers the ability to compare the pain data with real-time local weather.

Researchers reviewed data from participants in three cities – Leeds, Norwich and London – and found that as the number of sunny days increased from February to April, the amount of time participants spent in severe pain decreased.

Conversely, when the weather turned rainy and cloudy in June, the amount of time spent in severe pain increased.

The 18-month study is only half complete and researchers are still looking to recruit as many people as possible who are willing to track their symptoms.

“If you are affected by chronic pain, this is your chance to take do something personally – and easily – to lead to a breakthrough in our understanding of pain,” said lead investigator Will Dixon, a professor of Digital Epidemiology at The University of Manchester’s School of Biological Sciences.

The Greek philosopher Hippocrates in 400 B.C was one of the first to note that changes in the weather can affect pain levels. Although a large body of folklore has reinforced the belief that there is a link between weather and pain, the science behind it is mixed.

A 2014 study in Australia found that low back pain is not associated with temperature, humidity and rain.  A 2013 Dutch study also concluded that weather has no impact on fibromyalgia symptoms in women.

“Once the link is proven, people will have the confidence to plan their activities in accordance with the weather. In addition, understanding how weather influences pain will allow medical researchers to explore new pain interventions and treatments,” says Dixon.

People with arthritis or chronic pain who are interested in joining the Cloudy with a Chance of Pain project – and who have access to a smartphone – can download the app by clicking here. You need to be at least 17 and live in the UK.

Participants are encouraged to record their pain symptoms daily until the project ends in January.  Researchers hope to use data to develop “pain forecasts” based on weather predictions.

Study Finds Link Between Chronic Pain and Anxiety

By Pat Anson, Editor

A new study helps explain why so many chronic pain patients also suffer from anxiety or depression.

Researchers at the University of Vermont discovered that the body releases the same neurotransmitter in response to stress as it does to chronic neuropathic pain. The findings, published in the journal Biological Psychiatry, could lead to the development of a new and safer class of medication that could treat both pain and anxiety.

In studies on laboratory mice, researchers found that pain signals and the PACAP neurotransmitter (pituitary adenylate cyclase activating polypeptide) share the same pathway to the brain - the spino-parabrachiomygdaloid tract - which travels from the spinal cord to the amygdala, where the brain processes emotional behavior.

"Chronic pain and anxiety-related disorders frequently go hand-in-hand," says senior author Victor May, PhD, a professor of neurological sciences at the University of Vermont. "By targeting this regulator and pathway, we have opportunities to block both chronic pain and anxiety disorders."

May and his colleagues found that anxious behavior and pain hypersensitivity were significantly reduced when a PACAP receptor antagonist -- designed to block the release of the neurotransmitter -- was applied.

"This would be a completely different approach to using benzodiazepine and opioids - it's another tool in the arsenal to battle chronic pain and stress-related behavioral disorders," said May, who found in a previous study that PACAP was highly expressed in women exhibiting symptoms of post-traumatic stress disorder (PTSD).

May’s findings are important because anxiety and stress are currently treated with sedatives, benzodiazepines and other central nervous system (CNS) depressants. When taken with opioid pain medication, the combination of the drugs can lead to extreme sleepiness, respiratory depression, coma and death.

Yesterday, the U.S. Food and Drug Administration ordered new “black box” warning labels be put on all medications that contain opioids, benzodiazepines and CNS depressants, warning patients and physicians about the increased risk.

According to a 2015 study, over a third of the patients prescribed opioids for chronic musculoskeletal pain were given a sedative. And patients with a history of psychiatric and substance abuse disorders were even more likely to be co-prescribed opioids and sedatives.

Animal Studies Show Promise for Safer Opioids

By Pat Anson, Editor

Animal studies currently underway could hold the key to developing new opioid therapies that relieve pain without the risk of addiction, overdose and other harmful side effects.

Researchers at Wake Forest Baptist Medical Center in North Carolina have developed a pain killing compound -- called BU08028 – that relieves pain in monkeys without causing physical dependence. BU08028 is similar to buprenorphine, an opioid currently used to treat both pain and addiction.

"Based on our research, this compound has almost zero abuse potential and provides safe and effective pain relief," said Mei-Chuan Ko, Ph.D., professor of physiology and pharmacology at Wake Forest Baptist and lead author of the study published in the Proceedings of the National Academy of Sciences.

"This is a breakthrough for opioid medicinal chemistry that we hope in the future will translate into new and safer, non-addictive pain medications."

This study, which was conducted on 12 monkeys, targeted a combination of mu opioid receptors in the brain – the same receptors targeted in humans by existing opioid pain medication.

The Wake Forest researchers examined behavioral, physiological and pharmacologic factors and found that BU08028 blocked pain signals without the side effects of respiratory depression, itching or adverse cardiovascular events. In addition, the study showed pain relief lasted up to 30 hours in the monkeys and repeated administration did not appear to cause physical dependence.

"To our knowledge, this is the only opioid-related analgesic with such a long duration of action in non-human primates," said Ko. “Given the decades-long effort aimed at developing abuse-free opioid analgesics, BU08028 represents a major breakthrough for opioid medicinal chemistry.”

Ko plans further animal studies on related compounds to see if they have the same safety profiles as BU08028. If those studies are successful, he hopes to begin studies on humans with the ultimate goal of getting FDA approval for a new class of opioid medication.

The research is funded by the National Institutes of Health and National Institute on Drug Abuse.

Rat Study Targets Peripheral Nerves

Another animal study is taking a different approach to pain relief – by targeting nerves in peripheral tissue – not the mu opioid receptors in the brain and spinal cord.

In findings published in Cell Reports, researchers at the University of Texas found that targeting delta opioid receptors on sensory neurons in the peripheral tissue of laboratory rats produces fewer side effects and with much lower abuse potential.

"Being able to increase the responsiveness of peripheral opioid receptor systems could lead to a reduction in systemic opioid administration, thereby reducing the incidence of side effects," says senior study author Nathaniel Jeske of the University of Texas Health Science Center at San Antonio.

One complication is that delta opioid receptors in peripheral tissues only become activated in the presence of inflammation. Because it has not been clear how to overcome this need for an inflammation trigger, the development of drugs that target peripheral nerves has been limited.

Jeske and his colleagues discovered a protein called GRK2 that binds to and prevents delta opioid receptors on rat sensory neurons from responding normally to opioids. But when those peripheral nerves were exposed to a natural inflammatory molecule called bradykinin, GRK2 moved away from the delta opioid receptors, setting off a biochemical reaction that restored the functioning of these receptors.

In addition, rats with reduced GRK2 levels in peripheral sensory neurons regained sensitivity to the pain-relieving effects of a drug that activates delta opioid receptors, and without the need for an inflammatory trigger.

The researchers hope to replicate the same findings using human tissues.

"By shedding light on how inflammation activates delta opioid receptors, this research could potentially lead to the development of safer, more effective opioids for the treatment of pain," said Jeske, whose work is funded by the National Institutes of Health.

Do Men Get More Pain Relief From Marijuana?

By Pat Anson, Editor

Experts tell us that women are more likely to experience chronic pain than men, feel pain more intensely, and are more likely to be undertreated for pain than men are.

The gender gap in pain grew a little wider this week with a new study, published in Drug and Alcohol Dependence, which claims women get far less pain relief from smoking marijuana than men do.

"These findings come at a time when more people, including women, are turning to the use of medical cannabis for pain relief," said lead author Ziva Cooper, PhD, associate professor of clinical neurobiology at Columbia University Medical Center. "Preclinical evidence has suggested that the experience of pain relief from cannabis-related products may vary between sexes, but no studies have been done to see if this is true in humans."

Cooper and her colleagues conducted two double-blinded, placebo-controlled studies that looked at the analgesic effects of cannabis in 42 healthy recreational marijuana smokers – half of them men and half women.

All smoked marijuana at least four times a week prior to enrolling in the study. Participants were excluded if they had pain.

After smoking the same amount of cannabis or a placebo, the participants immersed one hand in a cold-water bath until the pain could no longer be tolerated. Following the immersion, the participants answered a short pain questionnaire.

Among those who smoked cannabis, men reported a significant decrease in pain sensitivity and an increase in pain tolerance. But the women who smoked cannabis did not experience a significant decrease in pain sensitivity, although they did report a small increase in pain tolerance shortly after smoking.

No gender differences were found in how intoxicated the participants felt or how much they liked the effect of cannabis.

“These results indicate that in cannabis smokers, men exhibit greater cannabis-induced analgesia relative to women,” said Cooper.  “Sex-dependent differences in cannabis’s analgesic effects are an important consideration that warrants further investigation when considering the potential therapeutic effects of cannabinoids for pain relief.”

A marijuana advocate and caregiver for patients in Rhode Island said she was shocked by the study findings.

"This study concerns me that some women will read this and not even try the most magical pain relief out there," said Ellen Lenox Smith, a columnist for Pain News Network. "We have never, in the nine years of growing for myself and as caregivers for patients, ever had a time that this was not successful because of one's sex. We have had equal amounts of men and women and the only person that did not have success was an elderly woman that was not able to follow the directions due to her anxiety of using it. That was due to the stigma from society, not the product."

Do women really respond differently to marijuana or is there a flaw in the study itself?

Previous research has found that women respond differently to the cold water test and have far less tolerance for pain induced by cold water immersion than men.

“Most studies have used some form of the cold pressor test in which subjects immerse their arm or hand in circulating cold water for a defined period of time, and their results support the hypothesis that cold pain sensitivity is more pronounced in females,” researchers reported in a 2009 review of nearly two dozen studies that used the cold water test.  “Based on the present set of studies, it appears that sex differences in cold pain are consistent, particularly for suprathreshold measures such as tolerance and pain ratings.”

The Columbia University study was funded by the U.S. National Institute on Drug Abuse. Ziva Cooper also received salary support from Insys Therapeutics, which is developing cannabis-based drugs.

‘Weird and Cool’ Discovery Could Lead to Safer Opioid

By Pat Anson, Editor

A “weird and cool” discovery by a team of international researchers could lead to the development of a new opioid medication that relieves pain without the risk of abuse and overdose.

In a case of reverse engineering, scientists in the U.S. and Germany deciphered the atomic structure of the brain’s mu-opioid receptor and then designed a drug – called PZM21 – that activates the receptor without the typical side effects of opioids. In experiments on mice, PZM21 did not cause drug-seeking behavior and did not interfere with breathing – the main cause of death in opioid overdoses.

“With traditional forms of drug discovery, you’re locked into a little chemical box,” said Brian Shoichet, PhD, a professor of pharmaceutical chemistry at UC San Francisco’s School of Pharmacy.

“But when you start with the structure of the receptor you want to target, you can throw all those constraints away. You’re empowered to imagine all sorts of things that you couldn’t even think about before.”

Shoichet and colleagues at Stanford University, the University of North Carolina and the Friedrich Alexander University in Erlangen, Germany published their findings in the journal Nature.

"This promising drug candidate was identified through an intensively cross-disciplinary, cross-continental combination of computer-based drug screening, medicinal chemistry, intuition and extensive preclinical testing," said Brian Kobilka, MD, a Nobel Prize winner and professor of molecular and cellular physiology at Stanford. It was Kobilka who first established the molecular structure of the opioid receptor.

Shoichet and his research team conducted roughly four trillion “virtual experiments” on UCSF computers, simulating how millions of different drug candidates could turn and twist in millions of different angles – called “molecular docking” -- to see how they fit into a pocket on the receptor and activate it. They avoided using molecules linked to the respiratory suppression and constipation typical of other opioids.

This led to the development of PZM21, which efficiently blocked pain in mice without producing the constipation and breathing suppression typical of other opioids. PZM21 also appears to dull pain by affecting opioid circuits in the brain only, with little effect on opioid receptors in the spinal cord. No other opioid has that effect, which Shoichet says is “unprecedented, weird and cool.”

The drug also didn’t produce the hyperactivity that other opioids trigger in mice by activating the brain’s dopamine systems. The mice did not display drug-seeking behavior by spending more time in chambers where they had previously received doses of PZM21.

“After we replicated the lab experiments and mouse studies several times, then I became excited about the potential of this new drug,” said Bryan Roth, MD, a professor of pharmacology and medicinal chemistry at University of North Carolina.

Researchers say more work is needed to establish that PZM21 is truly non-addictive, and to confirm that it is safe and effective in humans.

 “We haven’t shown this is truly non-addictive,” Shoichet cautioned. “At this point we’ve just shown that mice don’t appear motivated to seek out the drug.”

Is Chronic Pain a Family Affair?

By Pat Anson, Editor

We can credit – or blame – our parents for many things, including our eye color, hair color, height, weight, personality, even our cravings for certain foods.

And if our parents have chronic pain, we are also more likely to suffer from pain ourselves, according to research recently published in the journal Pain. 

“Offspring of parents with chronic pain are at increased risk for pain and adverse mental and physical health outcomes,” wrote co-authors Amanda Stone of Vanderbilt University and Anna Wilson of Oregon Health & Science University.

"Although the association between chronic pain in parents and offspring has been established, few studies have addressed why or how this relation occurs."

Stone and Wilson developed a “conceptual model” of how chronic pain can be transmitted from parent to child through genes, parenting, stress, and lifestyle choices.

"Such a framework highlights chronic pain as inherently familial and intergenerational, opening up avenues for new models of intervention and prevention that can be family-centered and include at-risk children," they wrote.

The researchers identify five "plausible mechanisms" to explain the transmission of chronic pain from parent to child:

• Genetics. Children of parents with chronic pain might be at increased genetic risk for sensory as well as psychological components of pain. Research suggests that genetic factors account for about half of the risk of chronic pain in adults.
• Early Neurobiological Development. Having a parent with chronic pain may affect the functioning of the nervous system during critical periods of child development. For example, a baby's development might be affected by the mother's stress levels or behavior during and after pregnancy.
• Social Learning. Children may learn "maladaptive pain behaviors" from parents, such as catastrophizing and excessive worrying about pain.
• Parenting and Health Habits. Chronic pain risk could be affected by parenting behaviors linked to adverse child outcomes--for example, permissive parenting or lack of consistency and warmth. The parents' physical activity level and other health habits might also play a role.
• Exposure to Stress. There may be adverse effects from growing up in stressful circumstances related to chronic pain -- for example, financial problems or parents' inability to perform daily tasks.

Other factors that may explain why some children are at greater risk include chronic pain in both parents, the location of the parent's pain, and the children's personal temperament.

"The outlined mechanisms, moderators, and vulnerabilities likely interact over time to influence the development of chronic pain and related outcomes," wrote Stone and Wilson, who hope their model will help guide future research toward developing early prevention and treatment approaches for children at risk of chronic pain.

Poor Fitness Leads to Childhood Pain

Another recent study in Finland found that poor physical fitness and sedentary behavior are linked to pain in children as young as 6-8 years of age.

The Physical Activity and Nutrition in Children (PANIC) study at the University of Eastern Finland analyzed the physical fitness, exercise, hobbies, body fat and various pain conditions in 439 children. Physically unfit children suffered from headaches more frequently than others. High amounts of screen time and other sedentary behavior were also associated with increased prevalence of pain conditions.

“Pain experienced in childhood and adolescence often persists later in life. This is why it is important to prevent chronic pain, recognize the related risk factors and address them early on. Physical fitness in childhood and introducing pause exercises to the hobbies of physically passive children could prevent the development of pain conditions,” the study found.

Doctors Warn of Crisis in Osteoporosis Treatment

By Pat Anson, Editor

Thirty years of progress in treating osteoporosis and reducing bone fractures in the elderly is rapidly being reversed, according to two bone health experts.

In an article called A Crisis in the Treatment of Osteoporosis, published in the Journal of Bone and Mineral Research, Sundeep Khosla, MD, and Elizabeth Shane, MD, say too many patients at high risk of fractures are not being diagnosed or treated for osteoporosis, even though hormones and bisphosphonate drugs are available to help strengthen their bones.

“The field of osteoporosis may be coming full circle, and that is not good for the millions of older women and men who will suffer painful and disabling spine and hip fractures - fractures that might have been prevented,” Khosla and Shane wrote.

“As physicians, we are now watching as the fundamental progress made to reduce fractures and dramatically improve the quality of life of our patients during the past 30 years unravels.”

More than 10 million Americans suffer from osteoporosis and 44 million have its precursor, a loss in bone density that raises the risk of fractures and disability.  Breaking a bone in your spine or hip may be so traumatic – especially for the elderly -- that it doubles your chances of developing chronic widespread body pain.

Bisphosphonates such as Fosamax have been found to be effective at slowing the loss of bone mass and reducing fractures, but concerns about their use rose when patients reported side effects such as joint and musculoskeletal pain. That made some patients reluctant to take bisphosphonates and doctors less likely to prescribe them.  

Khosla and Shane cite a recent study that found only 3 percent of patients with a hip fracture in 2013 were given bisphosphonates to strengthen their bones, down from 15% of patients in 2004.

“In short, we, as physicians who care deeply about the treatment of patients with osteoporosis, find ourselves in a dire situation. At a point in time when we have developed pharmacologic tools capable of preventing enormous suffering and needless mortality, we may well be coming back full circle: the downward spiral of vertebral fracture, hip fracture, immobility, loss of independence, and premature death that we thought we had conquered may soon become the accepted norm again,” they wrote. 

“There can be no more urgent call to action for our field than we face today. We must find ways to ensure that patients who need appropriate treatment for osteoporosis are not only prescribed effective medications, but are also equipped with the information they need to make an informed choice on taking these medications.”

Khosla is an endocrinologist, research scientist, professor of medicine and director of the Clinical and Translational Science Award Program at the Mayo Clinic in Rochester, Minnesota. Shane is an endocrinologist, research scientist, professor of medicine and vice chair for clinical and epidemiological research at Columbia University in New York.

A quarter-million Americans sustain a hip fracture each year, according to the National Osteoporosis Foundation, but less than a quarter are treated for osteoporosis afterwards.

A recent survey of 42 hip fracture patients found a startling level of misinformation and mismanagement surrounding osteoporosis. A majority (57%) said their doctors did not recommend osteoporosis medication and one in four said they would reject taking the drugs.

Nearly two-thirds (64%) of those who said they were being treated for osteoporosis were taking calcium and vitamin D supplements, which researchers say are "useless" at preventing osteoporotic fractures.

Another recent study found that elderly men are far less likely to be screened for osteoporosis or to take preventive measures against the bone-thinning disease than women. The risk of death after sustaining a hip fracture is twice as high in men compared to women.

Chronic Pain a ‘Silent Epidemic’ in UK

By Pat Anson, Editor

Nearly half of adults in the UK – nearly 28 million people – suffer from chronic pain, according to a new study in the British Medical Journal  that estimates about one in seven Britons have pain so severe it is disabling.

“Pain is really under-represented in terms of the public awareness of it,” lead author Alan Fayaz of Imperial College London said in The Guardian. “Nobody ever talks about chronic pain, it is like a silent epidemic.”

Fayaz and his colleagues conducted a meta-analysis of 19 studies involving nearly 140,000 people in the UK. Data from the studies was combined to arrive at the estimate that 43% of adults suffer from chronic pain – defined as pain that lasts for three months or more.

That estimate is over three times higher than a previous telephone survey study that found 7.8 million Britons have moderate to severe chronic pain.

About 8% of UK adults experience chronic neuropathic pain and 5.5% have fibromyalgia. Women are more likely to experience chronic pain than men.

Chronic pain was found to be a common experience among all age groups, including young adults, but increases steadily with age. Nearly two-thirds of adults over age 75 have chronic pain, according to one of the studies reviewed.

 “Bearing in mind that we are, in general an ageing population, that’s of concern because what you would then expect would be if you repeated this study in about 10 years time, the prevalence of chronic pain would be higher,” said Fayaz.

 “What I would really like is for us to have better tools in order for us to identify those people who are most severely affected and how we can help them, what their care needs are.”

The prevalence of chronic pain in the UK is similar to that in the United States, where the Institute of Medicine estimated that 40% of American adults – about 100 million people – have chronic pain.

New Molecules May Combat Immune System Disease

By Pat Anson, Editor

A team of international researchers may have unlocked an ancient secret in the human immune system that could lead to new treatments for rheumatoid arthritis, multiple sclerosis and inflammatory bowel disease (IBD).

"Innate immunity is so old it goes all the way down to frogs, fish and even insects," says Professor Matt Cooper of the University of Queensland’s Institute of Molecular Bioscience.

Cooper and colleagues at Kings College London and the U. S. National Institutes of Health say the human immune system is basically comprised of two parts: the adaptive immune system, which produces antibodies against infection, and a very ancient pathway, known as the innate immune system.

"It stops us getting infections, but it also drives a lot of inflammatory diseases,” explains Cooper.  "So, in one case it's keeping us alive by stopping the bugs getting us, but if it goes wrong, we start to get diseases like arthritis, multiple sclerosis and IBDs such as colitis.

"Researchers always thought key components of these pathways acted alone, but our teams have discovered they can communicate and work together."

IBD is a chronic and painful inflammation of the gastrointestinal tract. Inflammation affects the entire digestive tract in Crohn’s disease, but only the large intestine in ulcerative colitis.

The study findings, published in the journal Science, may have significant implications for treating millions of people who suffer from inflammatory diseases.

"Inflammation in diseases such as colitis occurs when the immune system is activated inappropriately, and causes symptoms including pain, diarrhea, fever and weight loss," said Cooper. "Current treatments are not always effective, possibly because they are only blocking one of the key pathways and inflammation still occurs through the other pathway."

Researchers have developed two small molecules that each block one pathway.

activated immune cells

"We have tested these molecules and the results show that they both reduce inflammation when administered separately," Cooper said. "This work is still in the early stages but we are hopeful our ongoing research will lead to more effective treatments for the millions of IBD sufferers.

"It may give other scientists opportunities to develop new drugs against these diseases."

A healthy immune system is activated when the body recognizes invading microbes and alerts immune cells, such as T cells. Disease begins when the immune response spirals out of control and begins attacking healthy tissue.  

Researchers at New York University’s Langone Medical Center are also working on a theory known as the "hygiene hypothesis" that may explain why there is an increase in inflammatory bowel disease worldwide. They believe intestinal parasites and bacteria that humans were long exposed to are beneficial and help balance the immune system.

Sanitary practices have sharply reduced these parasitic and bacterial infections in developed nations, which now have some of the highest rates of Crohn’s and colitis. Researchers believe the immune response to infections triggers the growth of Clostridia, a bacterium known to counter inflammation.

Painkillers Cause Chronic Pain? Rats!!!

By Pat Anson, Editor

A provocative new study is likely to stir fresh debate about the risks associated with opioid pain medication. It’s not another study about addiction or overdose, but whether opioids actually increase chronic pain, a condition known as hyperalgesia. 

An international team of researchers found that even just a few days of morphine can make chronic pain last for several months by intensifying the release of pain signals in the spinal cord.

But there’s a catch. The research was conducted on laboratory rats.

"We are showing for the first time that even a brief exposure to opioids can have long-term negative effects on pain," said Peter Grace, PhD, an assistant research professor at the University of Colorado-Boulder's Department of Psychology and Neuroscience. "We found the treatment was contributing to the problem."

Grace and his colleagues found that damaged nerve cells in rats send a message to spinal cord immune cells known as glial cells, which normally act as "housekeepers" to clear out unwanted debris and microorganisms. The first signal of nerve pain sends glial cells into alert mode, priming them for further action.

"I look at it like turning up a dimmer switch on the spinal cord," said Grace.

Nerve pain was induced in the rats by slicing open their thighs. A fine thread was then tied around a major nerve. Over the next three months, researchers poked the rats' paws with stiff nylon hairs to see how sensitive they were to pain.

Injured rats that were not treated with morphine eventually recovered and did not show pain, but those that were treated with morphine for five days remained sensitive to pain. Researchers believe the morphine stimulated their glial cells and sent them into overdrive. They liken the effect to being slapped in the face twice.

"You might get away with the first slap, but not the second," said co-author Linda Watkins, a Distinguished Professor at CU Boulder. "This one-two hit causes the glial cells to explode into action, making pain neurons go wild."

"The implications for people taking opioids like morphine, oxycodone and methadone are great, since we show the short-term decision to take such opioids can have devastating consequences of making pain worse and longer lasting," said Watkins. "This is a very ugly side to opioids that had not been recognized before."

Patient advocates had a mixed reaction to the study.

“Linda Watkins is doing some awesome work. We know that glial cells are the key to pain generation. Exactly how is still poorly understood,” said Terri Lewis, PhD, a rehabilitation specialist who teaches in the field of Allied Health.  “We know that 'something' triggers inflammation and maintains it. When that trigger is turned up high, glial cells are activated."

“Generalizing from rats to humans is not okay. But if the same results are found in pigs, there is probably something to talk about,” added Lewis.

“There is enough evidence in humans that opioids work and do not make pain worse,” said Janice Reynolds, a retired nurse and patient advocate.  “Even the work in hyperalgesia has not, contrary to claims by opiophobics, translated well from rats to humans. The write up is extremely negative and tends to lead one to believe the results may be slanted or even poorly interpreted. The fact they are singling ‘chronic pain’ out is a warning sign.”

The CU-Boulder study, which is published online in the Proceedings of the National Academy of Sciences, does have an impressive pedigree, including researchers at the University of Adelaide in Australia, the University of North Carolina, the Chinese Academy of Sciences, the National Institute on Drug Abuse, the National Institute on Alcohol Abuse and Alcoholism, and Tsinghua University in Beijing.

The study was funded in part by the American Pain Society, Australia's National Health and Medical Research Council, the National Natural Science Foundation in China, the National Institute on Drug Abuse, the National Institute of Dental and Craniofacial Research and the National Institute of Alcohol Abuse and Alcoholism.

Study: Some Brains ‘Hardwired’ for Chronic Pain

By Pat Anson, Editor

Why do some people develop chronic pain from an injury or illness, while others do not?

The answer to that question may really be all in our heads.

A groundbreaking study by scientists at Northwestern University and the Rehabilitation Institute of Chicago (RIC) found that some people are genetically predisposed to chronic pain because of brain “abnormalities” that raise their risk of developing chronic pain. The findings challenge long-standing views on the science of pain, which emphasize treating pain at the site of the initial injury.

"While simple, the logic of addressing problems at the site of an injury to remove pain has resulted in only limited success," said senior study author Marwan Baliki, PhD, a research scientist at RIC and an assistant professor of physical medicine and rehabilitation at Northwestern University Feinberg School of Medicine.

"The central processes of chronic pain have largely been ignored, so our research team set out to better understand the brain's role."

Baliki and his colleagues conducted the first longitudinal brain imaging study, which tracked 159 patients for three years following an acute back injury, along with 29 healthy control subjects.  

MRI brain scans were conducted on all of the participants five times during the course of the study.

The researchers found that patients who developed chronic pain from their back injury had a smaller hippocampus and amygdala compared to those who recovered from the injury and the healthy control subjects.

The hippocampus is the primary brain region involved in memory formation and retention, while the amygdala is involved in the processing of emotions and fear. In addition to size variations, these brain regions also showed differences in connections to the rest of the brain, particularly to the frontal cortex, an area involved in judgment.

Together, the researchers estimate that these brain differences accounted for about 60% of the chronic pain felt by participants.

Most importantly, the study also revealed that the volumes of the amygdala and hippocampus did not change over the course of the study, suggesting that those who developed chronic pain were genetically predisposed to it.  

"Here we establish that the gross anatomical properties of the corticolimbic brain, not the initial back pain, determine most of the risk for developing chronic pain," said first author Etienne Vachon-Presseau, PhD, a visiting postdoctoral fellow in physiology at Feinberg.

“As the anatomical risk factors were stable across 3 years, they were presumably hardwired and present prior to the event initiating back pain. These results pave the way for the development of novel and distinct approaches to prevention and treatment of chronic pain.”

The Northwestern and RIC study will be published in the June edition of the journal Brain.

Talking Turkey: How Food Plays a Role in Pain

By Pat Anson, Editor

There’s a nugget of truth to the old saying, “You are what you eat.” And no, we don’t mean chicken nuggets. We’re talking turkey.

Researchers at Brigham and Women's Hospital in Boston say changes in diet and gut bacteria appear to influence the activity of brain cells involved in controlling inflammation and neurodegeneration. They’ve published their study in the journal Nature Medicine

"For the first time, we've been able to identify that food has some sort of remote control over central nervous system inflammation," said corresponding author Francisco Quintana, PhD, an investigator in the Ann Romney Center for Neurologic Diseases at Brigham and Women’s Hospital.

"What we eat influences the ability of bacteria in our gut to produce small molecules, some of which are capable of traveling all the way to the brain. This opens up an area that's largely been unknown until now: how the gut controls brain inflammation."

While studying laboratory mice, Quintana and his colleagues found that gut bacteria produce molecules that influence astrocytes -- star-shaped cells that reside in the brain and spinal cord.

The molecules, which are derived from tryptophan (an amino acid found in turkey and other foods), act as fuel that helps the astrocytes limit brain inflammation.

In blood samples from patients with multiple sclerosis (MS) – a disease that attacks the body’s central nervous system -- the researchers found lower levels of these tryptophan-derived molecules.

"Deficits in the gut flora, deficits in the diet or deficits in the ability to uptake these products from the gut flora or transport them from the gut -- any of these may lead to deficits that contribute to disease progression," said Quintana.

MS is a chronic and incurable disease that causes numbness in the limbs, difficulty walking, paralysis, loss of vision, fatigue and pain.

In addition to turkey, tryptophan is found in other high-protein foods such as chicken, beef, nuts and cheese. Its a myth that eating lots of turkey will put you to sleep, according to the American Nutrition Association. But tryptophan does help produce serotonin, a neurotransmitter that regulates mood and mental activity,

Scientists are just beginning to recognize that food and gut bacteria play a role in multiple sclerosis and other chronic pain conditions.

Researchers at New York University’s Langone Medical Center recently found that some intestinal parasites and bacteria play a beneficial role in helping to balance the immune system, and reduce rates of inflammatory bowel diseases (IBD) such as Crohn’s disease and ulcerative colitis.

Sanitary practices have sharply reduced intestinal worm infections in developed nations, which now have some of the highest rates of Crohn’s and colitis. Scientists believe the worms help produce a certain type of bacteria that helps control inflammation. This “hygiene hypothesis” may also apply to MS, rheumatoid arthritis, type 1 diabetes, and other autoimmune diseases.

Study Finds Friendship ‘Stronger than Morphine’

By Pat Anson, Editor

People with more friends and large social networks have a higher tolerance for pain, according to a new study by researchers at Oxford University.

Scientists believe that social bonding activities such as music, dancing and laughter activate the body’s endogenous opioid system, releasing natural endorphins that not only make you feel better when seeing friends, but can also relieve pain.

“Endorphins are part of our pain and pleasure circuitry -- they're our body's natural painkillers and also give us feelings of pleasure,” says Katerina Johnson, a doctoral student at Oxford University, who is studying whether differences in neurobiology can explain why some people have larger social networks than others.

“To test this theory, we relied on the fact that endorphin has a powerful pain-killing effect -- stronger even than morphine.”

Johnson and her colleagues enrolled 107 healthy young adults in a squatting exercise to test their tolerance for pain. Participants were told to squat against the wall with their knees bent at a 90° degree angle, and to hold that position and endure the discomfort for as long as possible.

Questionnaires were also completed by the participants to measure their personality traits and physical fitness, and to see how often they interacted with friends.

Not surprisingly, people who were more fit were able to hold the squatting position longer. But so did people with larger social networks.  

“Obviously we had to bear in mind that fitter individuals may be able to endure this physical pain test for a longer length of time.  However, even when we take this into account, our results show that pain tolerance still significantly predicts network size,” Johnson wrote in an email to Pain News Network.

An unexpected finding was that fitter people in the study tended to have smaller social networks.

“It may simply be a question of time -- individuals that spend more time exercising have less time to see their friends. However, there may be a more interesting explanation -- since both physical and social activities promote endorphin release, perhaps some people use exercise as an alternative means to get their 'endorphin rush' rather than socializing,” she said.

Since only healthy people participated in the study, Johnson admits her research may not apply well to chronic pain patients. But since many pain patients are disabled and unable to work or participate in many social activities, there could be some lessons to learn.

“When considering chronic pain, it seems like it may be a vicious circle whereby the more an individual is in pain, the less interested they are in interacting socially with others and their smaller social networks may in turn result in reduced activity of the endorphin system (thereby worsening their pain).  Perhaps also individuals that are genetically predisposed to reduced endorphin activity (and lower social motivation) are more likely to develop chronic pain conditions,” Johnson wrote.

“Another finding of our study was that individuals with smaller social networks tend to be more stressed, and stress is also thought to exacerbate pain.  However, clearly the underlying neurochemistry in pain responses is complex, though the endorphin system is heavily implicated in pain responses given its potent analgesic properties.”

The study findings are reported online in the journal Scientific Reports. 

What Does Your Pain Feel Like?

By Pat Anson, Editor

Does your chronic pain feel like you’ve been hit with a hammer, a bad sunburn that won’t go away, or ants crawling under your skin?

Those are some of the choices patients have in a new campaign launched in Ireland to change the way patients describepain to their physicians.   

Accurately assessing pain is difficult because pain is so subjective. For many years doctors have relied on various versions of the Wong Baker Pain Scale – a series of sad and smiling faces a patient chooses from to help their doctor understand how much pain they are in. The scale is so simple it was originally developed for children, but is now used around the world for adults.

The “Mypainfeelslike…” campaign aims to improve on that method by using more descriptive images and phrases to help doctors understand and diagnose their patient’s pain. The campaign focuses on neuropathic pain, but can be used for many other types of chronic pain. The initiative is sponsored by Grunenthal Group, a German pharmaceutical company.

Instead of an unhappy face, patients can choose from a dozen images, ranging from a burning flame to a rope tied in knots to a set of ice cubes. They also fill out a questionnaire and select different phrases to describe their pain, such as “a hot iron on my skin” or “a volcano erupting.”

Patients are also asked to fill out a questionnaire to select different phrases to describe their pain, such as “a hot iron on my skin” or “a volcano erupting.” And there's a list of multiple choice answers to describe how pain affects their ability to work, exercise and socialize.

It may take a few minutes to complete the questionnaire, but the idea is to get patients to “invest more time and accurateness in thinking about their symptoms, describing them more precisely, and preparing for doctors’ appointments.”

“Doing so forces us to reconsider our chronic pain, and the different ways that we feel it. This improves our self-awareness, allows us to better communicate our situation, and helps us get the most value out of the very short time that we usually have during doctors’ appointments,” the website says.

To take the questionnaire, click here.

According to a survey by Grunenthal, over half of Irish pain sufferers feel frustrated when trying to communicate their pain to a doctor. Over a quarter say they delay discussing their pain because they’re not sure how to do it.

“Living with chronic or nerve pain affects people’s well-being, their ability to be independent, their productivity and relationships, which can lead to feelings of depression," John Lindsay, chair of Chronic Pain Ireland told the Irish Independent.  “The ‘Mypainfeelslike…’ campaign will help raise awareness of the impact of chronic pain and give people living with this disease the tools to re-evaluate their pain management plans.”