Sex Differences in Inflammatory Biomarker Levels in Patients With Acute Myofascial Pain Syndrome: Observational Study.

INTRODUCTION

One of the most common chronic musculoskeletal pain disorders is myofascial pain syndrome (MPS). A previous study showed that the levels of inflammatory mediators and growth factors were elevated in MPS. The objective of the current study was to examine sex differences in inflammatory mediators in patients with acute MPS and asymptomatic controls.

METHODS

This cross-sectional study included a total of 57 patients (33 females; 24 males) clinically diagnosed with acute MPS who were consecutively recruited from the hospital emergency department, and 31 healthy subjects (12 females; 19 males) who were recruited via advertisements in the hospital and community. Serum inflammatory mediators and growth factors were measured in patients with MPS within 24 hours of symptoms and in healthy controls, using antibody-immobilized beads on a Luminex analyzer.

RESULTS

The levels of inflammatory mediators and growth factors were significantly higher in patients with MPS compared with healthy controls. No significant sex differences were observed in the MPS group in the levels of tumor necrosis factor-α (TNF-α), monocyte chemoattractant protein-1 (MCP-1), interleukin-8 (IL-8), macrophage inflammatory protein-1α (MIP-1α), interleukin-1α (IL-1α), fibroblast growth factor-2 (FGF-2), or platelet-derived growth factor (PDGF). Similarly, in healthy controls, no sex differences were found in TNF-α, MCP-1, IL-8, MIP-1α, MIP-1β, IL-1α, granulocyte-macrophage colony-stimulating factor (GM-CSF), or PDGF levels. Median G-CSF levels were significantly higher in males with MPS 103.0 (48.0-211.5) compared with females 51.7 (31.0-77.8) with MPS (χ(3) = 16.02, p < .05), while no sex differences were found in healthy controls. In males compared with females with MPS, there was a trend of higher median levels of GM-CSF, MIP-1β, and vascular endothelial growth factor. In healthy males compared with female controls, the levels of FGF-2 (105.2 [56.1-137.6] vs. 59.5 [38.8-80.7], χ(3) = 20.14, p = .04) and GM-CSF (19.9 [9.1-47.6] vs. 8.3 [4.2-11.9], χ(3) = 16.02, p = .03) were significantly higher.

CONCLUSION

The levels of several of the inflammatory mediators assessed in this study were elevated to a similar extent in both healthy males and females and those with acute MPS.