Pain research yielding encouraging discoveries, but funding cuts threaten future advances

"Pain scientists have made excellent progress in furthering our understanding of the biological, psychosocial, neurological and genetic mechanisms that govern pain stimuli," said APS President Roger Fillingim, PhD, a behavioral psychologist. "Such discoveries also are showing there are distinct neurobiological foundations for chronic pain that are significantly different from acute pain mechanisms. These are exciting and frustrating times in pain research. We're excited by the superb results emerging from pain research laboratories worldwide. The frustration comes from knowing we need to learn much more about the pathophysiology of pain and realizing that future government funding for pain studies could decline sharply," he said.

Fillingim added that current federal agency funding for pain research is terribly out of sync with the widespread incidence of chronic pain, estimated at 100 million by the Institute of Medicine. Budget slashing at the National Institutes of Health brought on by the sequester has painted a very uncertain picture for future pain research funding.

Understanding Pain Mechanisms

Psychologist Mark Jensen, PhD, editor of The Journal of Pain, a leading peer-reviewed pain research journal, noted multidisciplinary research efforts are building knowledge about pain and pain treatments. "We now know much more about pain mechanisms shared across different conditions. And this understanding is beginning to translate to new pain treatments that treat these mechanisms," said Jensen.

He added that recent emphasis on studying the brain and how it influences pain perceptions is showing that treatments aimed at "rewiring" brain signals can disrupt pain stimuli transmitted from the spinal cord to the brain.

"Studies at Stanford University and other sites are showing how brain stimulation can activate areas of the brain that provide pain relief and suppress pain stimuli," said Jensen. "Strategies that teach patients control over brain activity, such as meditation and self-hypnosis are showing promise as well. These and other studies are helping improve our understanding of how the brain governs pain, and this helps researchers build an empirical basis for understanding underlying mechanisms for various treatment approaches."

Risk Factors for Chronic Pain

"While we have adequate knowledge of many of the bio-psychosocial and genetic factors that contribute the perception of acute and chronic pain, a coordinated national public and private effort is required to successfully translate current knowledge into clinical practice," said William Maixner, DDS, PhD, a prominent pain researcher at the University of North Carolina School of Dentistry.

Maixner believes that pain research should focus more on learning risk factors for chronic pain similar to landmark studies that identified risks for cardiovascular disease. "I'm hopeful that data generated by the OPPERA (Orofacial Pain: Prospective Evaluation and Risk Assessment) population-based study will provide meaningful insights regarding risk factors for TMJD (temporomandibular joint disorder)pain similar to what the Framingham Heart Study did to expand knowledge about risks for heart attacks. This could lead to development of effective pain prevention strategies." Sponsored by the National Institute of Dental and Craniofacial Research (NIDCR), OPPERA is the first large, prospective clinical study to identify risk factors for developing TMJD.

Other key pain research achievements

Genetics: Studies investigating several potential molecular pain markers could lead to personalized medicine approaches to pain management that combine molecular diagnostic testing to identify gene abnormalities associated with pain syndromes with new, highly targeted, gene-based therapies.

The Role of Neurotransmitters: The neurotransmitters epinephrine, norepinephrine and dopamine are known to be integral components regulating pain stimuli from the brain. An enzyme called COMT influences concentrations of neurotransmitters in pain pathways. Levels of COMT have been found to be predictive of pain responses and may account for variations in pain sensitivities.

Glial Cells: Research has shown that housekeeping cells called glia release biochemicals that stimulate spinal cord neurons and neurotransmitters responsible for relaying pain messages to the brain. Once activated, glial cells can exaggerate a non-protective pain response. Researchers are working to develop drugs that can selectively block the harmful action of glial cells.

Cognitive-Behavioral Therapy: In the last decade, numerous studies have shown the benefits of cognitive-behavioral approaches to pain management in helping people with chronic pain cope better and lead productive lives. For example, recent studies using hypnosis as a pain therapy have shown how hypnosis operates in the central nervous system and the potential for using hypnotic suggestion to decrease pain severity.

"The nation's pain research agenda is robust and designed to confront the reality that current pain treatments only help a small percentage of people with chronic pain and, that some medications have serious side effects and risks for misuse. But, at this point, we really can't predict which patients will benefit from which treatments," said Fillingim.

"A key task for pain researchers, therefore, is to continue to develop our understanding about the pathophysiology of pain and be able to better match patients with effective treatment and harness the promise of personalized medicine to develop, new gene-based approaches to pain management. Fulfilling the promise of pain research, however, depends on being able to fund the studies that someday will make the difference in the lives of chronic pain patients."