UNALTERED LOW NERVE GROWTH FACTOR AND HIGH BRAIN-DERIVED NEUROTROPHIC FACTOR LEVELS IN PLASMA FROM PATIENTS WITH FIBROMYALGIA AFTER A 15-WEEK PROGRESSIVE RESISTANCE EXERCISE

Background: The pathophysiology of fibromyalgia includes central and peripheral factors. Neurotro-phins, such as nerve growth factor and brain-derived neurotrophic factor, are involved in peripheral and central nervous system development of pain and hyperalgesia. Few studies have examined circulating nerve growth factor and brain-derived neurotrophic factor in fibromyalgia or have investigated whether exercise interventions affect the levels of these peptides. Objectives: To compare plasma levels of nerve growth factor and brain-derived neurotrophic factor in fibromyalgia and in healthy controls, to investigate correlations between levels of nerve growth factor, brain-derived neurotrophic factor, and cytokines and clinical variables, and to investigate the effect of exercise on these levels. Subjects and methods: A total of 75 women with fibromyalgia participated in blood tests at baseline and after the 15-week intervention, and 25 healthy controls participated at baseline. Patients were randomized to a 15-week progressive resistance exercise intervention or a relaxation intervention. Results: Brain-derived neurotrophic factor level was significantly higher (p amp;lt;0.001) and nerve growth factor level was significantly lower (p amp;lt;0.001) in fibromyalgia than in healthy controls. Neither resistance exercise nor relaxation interventions affected the levels of brain-derived neurotrophic factor or nerve growth factor. No significant correlations were found between brain-derived neurotrophic factor or nerve growth factor plasma levels in fibromyalgia and cytokine levels or clinical variables. Conclusion: Changes in circulating nerve growth factor and brain-derived neurotrophic factor levels may affect nociception/pain in fibromyalgia. Clinical improvements were achieved following the exercise intervention, but the levels of brain-derived neurotrophic factor and nerve growth factor were not normalized.Funding Agencies|Swedish Rheumatism Association; Health and Medical Care Executive Board of Vastra Gotaland Region; Stockholm County Council (ALF)Stockholm County Council; ALF grants at Region Ostergotland; Linkoping University Hospital Research Fund; Swedish Research CouncilSwedish Research Council [K2013-52X-22199-01-3, K2015-99x-21874-05-4, 521-2010-2893]; AFA Insurance [140341]; ALF-LUA at Sahlgrenska University Hospital