Journal of Rehabilitation Medicine 51-10

J Rehabil Med 2019; 51: 779–787 ORIGINAL REPORT 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 Anna JABLOCHKOVA, Med. Stud. 1, *, Emmanuel BÄCKRYD, MD, PhD 1, *, Eva KOSEK, MD, PhD 2,3 , Kaisa MANNERKORPI, PT, PhD 4,5 , Malin ERNBERG, DDS, PhD 6 , Björn GERDLE, MD, PhD 1, ** and Bijar GHAFOURI, PhD 1, ** From the 1 Pain and Rehabilitation Centre, and Department of Medical and Health Sciences, Linköping University, Linköping, 2 Department of Clinical Neuroscience, Karolinska Institutet, 3 Department of Neuroradiology and Department of Perioperative Medicine and Intensive Care, Karolinska University Hospital, Stockholm, 4 Department of Neuroscience and Physiology, Section of Health and Rehabilitation, Physiotherapy, Sahlgrenska Academy, University of Gothenburg, 5 University of Gothenburg Centre for Person Centred Care (GPCC), Sahlgrenska Academy, Göteborg and 6 Department of Dental Medicine, Karolinska Institutet, and Scandinavian Centre for Orofacial Neurosciences (SCON), Huddinge, Sweden *These authors are joint first authors. **These authors are joint last authors. 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 hy- peralgesia. 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 pep- tides. Objectives: To compare plasma levels of nerve growth factor and brain-derived neurotrophic factor in fibromyalgia and in healthy controls, to investiga- te correlations between levels of nerve growth fac- tor, 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 ran- domized to a 15-week progressive resistance exer- cise intervention or a relaxation intervention. Results: Brain-derived neurotrophic factor level was significantly higher (p < 0.001) and nerve growth factor level was significantly lower (p < 0.001) in fi- bromyalgia than in healthy controls. Neither resis- tance exercise nor relaxation interventions affec- ted the levels of brain-derived neurotrophic factor or nerve growth factor. No significant correlations were found between brain-derived neurotrophic fac- tor or nerve growth factor plasma levels in fibromy- algia 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 neuro- trophic factor and nerve growth factor were not nor- malized. Key words: brain-derived neurotrophic factor; biomarker; chronic pain; fibromyalgia; nerve growth factor; plasma. Accepted Aug 16, 2019; Epub ahead of print Aug 30, 2019 LAY ABSTRACT Patients with fibromyalgia have treatment-resistant chronic pain. More research is needed in order to un- derstand how and why fibromyalgia develops. Neuro- trophins, such as nerve growth factor and brain-derived neurotrophic factor, are involved in peripheral and cen- tral nervous system development of pain and hyperal- gesia, but 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. This study compared blood levels of nerve growth factor and brain-derived neurotrophic factor in fibromyalgia with those in healthy controls, and investigated the effect of exercise on these levels. Brain-derived neurotrophic factor levels were higher and levels of nerve growth fac- tor were lower in fibromyalgia, compared with healthy controls. Clinical improvements were achieved following the exercise intervention, but the levels of brain-derived neurotrophic factor and nerve growth factor were not normalized. J Rehabil Med 2019; 51: 779–787 Correspondence address: Emmanuel Bäckryd, Pain and Rehabilitation Centre and Department of Medical and Health Sciences, Linköping Uni- versity, SE 581 85 Linköping, Sweden. E-mail: emmanuel.backryd@ regionostergotland.se F ibromyalgia (FM) is a characterized by chronic widespread pain and generalized hyperalgesia. FM in the western world has high comorbidity with other chronic pain conditions and somatic and psychological symptoms/disorders. The prevalence of FM is 2–8%, depending on the diagnostic criteria used. No definite pathophysiology has been established. Anatomical and functional changes in the brain, neuroinflam- mation including activation of glia cells, opioidergic dysregulation, nociception-driven amplification of neural signalling (central sensitization), and impaired top-down modulation have been reported, as well as systemic low-grade inflammation and nociceptor and muscle alterations (1–6). Taken together, these altera- This is an open access article under the CC BY-NC license. www.medicaljournals.se/jrm Journal Compilation © 2019 Foundation of Rehabilitation Information. ISSN 1650-1977 doi: 10.2340/16501977-2593

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