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RESEARCHERS DISCOVER A RATIONAL BIOLOGICAL SOURCE OF PAIN IN THE SKIN OF PATIENTS WITH FIBROMYALGIA
RENSSELAER, N.Y., June 20, 2013 /PRNewswire/ -- Fibromyalgia, a painful condition affecting approximately 10 million people in the U.S., is not imaginary after all, as some doctors have believed. A discovery, published this month in PAIN MEDICINE (the journal of the American Academy of Pain Medicine) at http://www.ncbi.nlm.nih.gov/pubmed/23691965, shows that fibromyalgia may have a rational biological basis located in the skin.
Characterized by subjective complaints of widespread deep tissue pain, tenderness in the hands and feet, fatigue, sleep disorders, and cognitive decline, the disorder was widely considered as psychosomatic ("imagined in the head"). Imaging techniques have recently revealed increased brain activity in pain centers, but the source for this hyperactivity activity is unknown.
Now, a breakthrough discovery by scientists at Integrated Tissue Dynamics LLC (Intidyn) has provided a biological rationale for this enigmatic disease. The company, founded by neuroscientists Dr. Frank L. Rice and Dr. Phillip J. Albrecht, utilized a unique multi-molecular ChemoMorphometric Analysis (CMA) to evaluate nerve fibers within small skin biopsies. The study was limited to women who are more than twice as likely to be afflicted by fibromyalgia as men.
"We detected extremely excessive sensory nerve fibers around blood vessels in the palms of the hands," said Dr. Rice. "This discovery provides concrete evidence of a fibromyalgia-specific pathology that is clearly outside of the brain. This could be used to facilitate the diagnosis of the disease and provide a new target for the development of truly effective therapeutics."
Performed in collaboration with Albany Medical Center neurologists Dr. Charles E. Argoff and Dr. James Wymer and Dr. James Storey of Upstate Clinical Research Associates (Albany, NY), the study was funded by Forest Laboratories and Eli Lilly. Both pharmaceutical companies have developed FDA-approved medications with similar functions (Serotonin/Norepinephrine Reuptake Inhibitors, SNRI) that provide at least some degree of relief for many fibromyalgia patients.
"Knowing how these drugs were supposed to work on molecules in the brain," Dr. Albrecht added, "we had evidence that similar molecules were involved in the function of nerve endings on the blood vessels. Therefore, we hypothesized that fibromyalgia might involve a pathology in that location." As the results demonstrate, they were correct.
A Thermostat for the Skin
Importantly, the excessive nerve fibers were concentrated around tiny muscular valves, called arteriole-venule (AV) shunts (see diagram). In humans, these shunts are found in the palms of our hands and soles of our feet and work like the radiator in a car. In warm conditions, the shunts close, which forces blood into the capillaries at the skin surface to radiate heat from the body. Under cold conditions, the shunts open allowing blood to bypass the capillaries to conserve heat, which is why our hands get cold.
According to Dr. Albrecht, "the excess sensory innervation may explain why fibromyalgia patients typically have especially tender and painful hands."
Noting that blood flow to the hands is normally known to be diverted to muscles during exercise, Dr. Rice proposes that "That mismanaged blood flow due to malfunctioning shunts could also interfere with blood flow to the muscles throughout the body. This could be the source of wide spread muscular pain, achiness and fatigue which are thought to be due to a build-up of lactic acid and low levels of inflammation fibromyalgia patients. This, in turn, could contribute to the hyperactivity in the brain."
A description of this study for the general public can be found at: http://www.intidyn.com/Newsroom/article-0008.html