Supplementary Material for: Circulating Matrix Metalloproteinase-9 Level Is Associated with Cerebral White Matter Hyperintensities in Non-Stroke Individuals

<b><i>Backgrounds:</i></b> The pathogenesis of cerebral white matter hyperintensities (WMH) has been poorly understood. Our aim was to investigate the association of circulating proteins, the biomarkers of inflammation, blood-brain barrier (BBB) dysfunction, and thrombosis with WMH in non-stroke individuals. <b><i>Methods:</i></b> Demographic, laboratory, and brain magnetic resonance imaging parameters were prospectively analyzed in 137 subjects. The relationship between plasma interleukin-6, tumor necrosis factor-α, matrx-metalloproteinase-9 (MMP-9), plasminogen activator inhibitor-1 and overt WMH (Fazekas grading score ≥2) was analyzed. <b><i>Results:</i></b> In univariate analysis, old age, high blood pressure, history of hypertension, and elevated plasma MMP-9 level were associated with overt WMH. In multivariate analysis, plasma MMP-9 still maintained a significant association with WMH. Plasma MMP-9 level was weakly but significantly associated with WMH volume (r = 0.232, p = 0.006). All the other circulating proteins examined failed to demonstrate a significant relationship with WMH. <b><i>Conclusions:</i></b> Plasma MMP-9 is associated with pathophysiology of WMH development.