Increased Interstitial Concentrations of Glutamate and Pyruvate in Vastus Lateralis of Women with Fibromyalgia Syndrome Are Normalized after an Exercise Intervention - A Case-Control Study

• Published in: PloS one 2016-10, Vol.11 (10), p.e0162010-e0162010
• Main Authors: Gerdle, Björn, Ernberg, Malin, Mannerkorpi, Kaisa, Larsson, Britt, Kosek, Eva, Christidis, Nikolaos, Ghafouri, Bijar
• Format: Article
• Language: English
• Subjects: Aging; Amino acids; Arthritis; Biology and Life Sciences; Blood flow; Blood pressure; Case-Control Studies; Chronic illnesses; Chronic pain; chronic widespread pain; Dentistry; Diabetes; Durability; Endurance; Exercise therapy; Exercise Therapy - methods; Extracellular Fluid - chemistry; Extremities; Female; Females; Fibromyalgia; Fibromyalgia - therapy; Fitness training programs; Glucose; Glutamate; Glutamic Acid - analysis; Glycerol; Health sciences; Humans; Hypertension; In vivo methods and tests; Intervention; lactate concentrations; Lactates; Lactic acid; Medical research; Medicin och hälsovetenskap; Medicine; Medicine and Health Sciences; Metabolites; Microdialysis; Middle Aged; muscle; muscle blood-flow; Muscles; musculoskeletal pain; neck-shoulder pain; Neurosciences; nitric-oxide; Pain; Physical Sciences; Physical training; Physiotherapy; Pyruvic acid; Pyruvic Acid - analysis; Quadriceps Muscle - chemistry; randomized controlled-trial; Rehabilitation; Resistance training; Rheumatology; Sjukgymnastik; skeletal-muscle; Stress; Studies; trapezius; whiplash-associated disorders
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0162010

Fibromyalgia syndrome (FMS) is associated with central alterations, but controversies exist regarding the presence and role of peripheral factors. Microdialysis (MD) can be used in vivo to study muscle alterations in FMS. Furthermore for chronic pain conditions such as FMS, the mechanisms for the positive effects of exercise are unclear. This study investigates the interstitial concentrations of algesics and metabolites in the vastus lateralis muscle of 29 women with FMS and 28 healthy women before and after an exercise intervention. All the participants went through a clinical examination and completed a questionnaire. In addition, their pressure pain thresholds (PPTs) in their upper and lower extremities were determined. For both groups, MD was conducted in the vastus lateralis muscle before and after a 15-week exercise intervention of mainly resistance training of the lower limbs. Muscle blood flow and interstitial muscle concentrations of lactate, pyruvate, glutamate, glucose, and glycerol were determined. FMS was associated with significantly increased interstitial concentrations of glutamate, pyruvate, and lactate. After the exercise intervention, the FMS group exhibited significant decreases in pain intensity and in mean interstitial concentrations of glutamate, pyruvate, and glucose. The decrease in pain intensity in FMS correlated significantly with the decreases in pyruvate and glucose. In addition, the FMS group increased their strength and endurance. This study supports the suggestion that peripheral metabolic and algesic muscle alterations are present in FMS patients and that these alterations contribute to pain. After an exercise intervention, alterations normalized, pain intensity decreased (but not abolished), and strength and endurance improved, all findings that suggest the effects of exercise are partially peripheral.