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.

Björn Gerdle,Kaisa Mannerkorpi,Malin Ernberg,Eva Kosek,Britt Larsson,Nikolaos Christidis,Bijar Ghafouri,Mario D Cordero

doi:10.1371/journal.pone.0162010

Björn Gerdle, Kaisa Mannerkorpi + Show 6 more

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https://doi.org/10.1371/journal.pone.0162010

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Abstract

BackgroundFibromyalgia 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.MethodsAll 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.ResultsFMS 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.ConclusionThis 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.

Highlights

Fibromyalgia syndrome (FMS) is a common chronic pain condition associated with negative implications [1,2]
Biochemical Alterations Normalized after Exercise in Fibromyalgia
The levels of glutamate, pyruvate and glucose had decreased after the 15-week exercise intervention and the decreases in two of these substances correlated with decreases in pain intensity it must be noted that FMS was not pain free after the exercise intervention

Summary

Introduction

Fibromyalgia syndrome (FMS) is a common chronic pain condition associated with negative implications [1,2]. Several MD studies have found increased concentrations of glutamate, serotonin, lactate, and/or pyruvate in the trapezius muscle in regional chronic neck pain conditions [26,27]. The latter study reported that the concentrations of glutamate and lactate correlated with pressure pain thresholds (PPTs) of trapezius and pain intensity in the FMS/CWP group [30]. Even though the two groups differed significantly on the two scales concerning anxiety and depression (Table 1), FMS did not show levels indicating anxiety or depression Prominent group differences were found for the two quality of life indices: SF36PCS and SF36-MSC Both groups had a high participation rate in the 15-week exercise intervention and no significant group difference existed: CON: 93 ± 12% vs FMS: 92 ± 10%, p = 0.605

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