Biomarkers alterations in trapezius muscle after an acute tissue trauma: A human microdialysis study

Abstract Aims Alteration in muscle milieu has been proposed as one of the main contributors underlying chronic musculoskeletal pain (CMP). Microdialysis (MD) provides real-time information on release of pain and metabolic biomarkers in muscle. However, insertion of MD probe causes a local tissue trauma, which may affect the tissue milieu. Whether an acute tissue trauma alter pain and metabolite biomarkers in trapezius muscle of patients with CMP is not known. Hence, this study investigated changes in muscle metabolites following MD probe insertion in patients with CMP in comparison with healthy controls. Methods Nineteen patients (11 women and 8 men; 41.4 years) with CMP and 20 pain-free volunteers (10 women and 10 men; 36.5 years) were recruited (project approval number: 2013/151- 31). Baseline pressure pain thresholds (PPT) at trapezius muscle were obtained bilaterally with a reference point at the tibialis muscle. Pain questionnaires were used for determining levels of anxiety and depression and catastrophizing impact. Interstitial samples were collected from trapezius muscles by aid of MD (20 kDa cut-off) during a period of 40 min. Collected dialysates at 2 time-points of 20 and 40 min were stored at −70 °C until analysis. Concentrations of glucose, lactate, pyruvate, glycerol, and glutamate were analyzed by ISCUSS flex . P ≤ 0.05 was considered significant. Results No potential case with respect to anxiety, depression or catastrophizing impact was found. Lower PPTs were found in CMP group ( P ≤ 0.05). Significantly lower levels of pyruvate were found in CMP group at both 20 min ( P = 0.003) and 40 min ( P = 0.006). Gender-based analysis indicated higher concentrations of glutamate in female patients with CMP. Conclusions This study was first to demonstrate metabolite alterations during trauma phase of MD in trapezius muscles of CPM compared with healthy controls. This model proved beneficial for investigating pain and metabolic biomarkers during acute phase of MD.