Circulating biomarkers in acute myofascial pain: A case-control study

Abstract

The aims of the present study were to compare levels of circulating inflammatory biomarkers and growth factors between patients with myofascial pain syndrome (MPS) and healthy control participants, and to assess the relationship among inflammatory markers and growth factors in the two groups.Biomarkers levels were assessed in patients (n = 37) with myofascial pain complaints recruited from the hospital emergency department and non-MPS controls (n = 21), recruited via advertisements in the hospital and community.Blood levels of the cytokines, namely, interleukin-6 (IL-6), tumor necrosis factor (TNF), and interleukin-12 (IL-12), and the chemokine, namely, monocyte chemoattractant protein-1 (MCP-1), macrophage-derived chemokine (MDC), eotaxin, granulocyte-macrophage colony-stimulating factor (GM-CSF), interleukin-8 (IL-8), and macrophage inflammatory proteins-1β (MIP-1β) were significantly higher in patients with MPS than controls. The results of the growth factor analyses revealed significantly higher levels of fibroblast growth factor-2 (FGF-2), platelet-derived growth factor (PDGF), and vascular endothelial growth factor (VEGF) in MPS patients versus controls. The pattern of correlation coefficients between cytokines and growth factors differed considerably for MPS patients and controls with far fewer significant positive coefficients observed in the controls. Serum inflammatory and growth factor biomarkers were elevated in MPS patients.Inflammatory biomarkers and growth factor levels may play an important role in the onset and maintenance of MPS and therefore may be useful in the diagnosis and treatment of MPS. Understanding the mechanisms of inflammation in MPS necessitates future research.

Figure 1

(A, B) Levels of cytokines in patients with MPS and healthy controls. The levels of the cytokines IL-6, TNF, and IL-12 were significantly higher in patients compared with those of healthy controls. Data are presented as mean ± SEM or as medians and interquartile ranges (25th and 75th percentiles). IL-6 =  interleukin-6, IL-12 =  interleukin-12, MPS = myofascial pain syndrome, TNF = tumor necrosis factor, SEM = standard error of the means.

Figure 2

(A, B) Levels of chemokines in patients with MPS and healthy controls. The levels of the chemokines MCP-1, MDC, eotaxin, GM-CSF, IL-8, and MIP-1β were significantly higher in patients with MPS compared with those of healthy controls. Data are presented as mean ± SEM or as medians and interquartile ranges (25th and 75th percentiles). GM-CSF = granulocyte-macrophage colony-stimulating factor, IL-8 = interleukin-8, MCP-1 = monocyte chemoattractant protein-1, MDC = macrophage-derived chemokine, MIP-1β =  macrophage inflammatory proteins-1β, MPS = myofascial pain syndrome, SEM = standard error of the means.

Figure 3

(A, B) Growth factors levels in patients with MPS and healthy controls. Growth factors FGF-2, PDGF, and VEGF levels were significantly elevated in patients compared with those of healthy controls. Data were presented as mean ±  SEM or as medians and interquartile ranges (25th and 75th percentiles). FGF-2 = fibroblast growth factor-2, MPS = myofascial pain syndrome, PDGF = platelet-derived growth factor, SEM = standard error of the means, VEGF = vascular endothelial growth factor.

Figure 4

(A, B) Relationship between inflammatory markers and growth factors in patients with MPS. In patients with MPS, there were strong positive correlations between the levels of growth factor FGF-2 and GM-CSF and MIP-1β. FGF-2 = fibroblast growth factor-2, GM-CSF = granulocyte-macrophage colony-stimulating factor, MIP-1β =  macrophage inflammatory proteins-1β, MPS = myofascial pain syndrome.

Figure 5

Relationship between inflammatory markers and growth factors in patients with MPS. In patients with MPS, there was a strong positive correlation between the levels of growth factor VEGF and TNF-α. MPS = myofascial pain syndrome, TNF-α = tumor necrosis factors, VEGF = vascular endothelial growth factor.