Serum matrix metalloproteinase-9 and tissue inhibitor of metalloproteinase-1 levels in patients with tick-borne encephalitis

Abstract

Matrix metalloproteinase-9 (MMP-9) and tissue inhibitor of metalloproteinase-1 (TIMP-1) play important roles in the function of the blood-brain barrier (BBB). To investigate the function of the BBB during tick-borne encephalitis (TBE), the levels of MMP-9 and its common tissue inhibitor, TIMP-1, were measured in serum from patients with acute phase of TBE. Serum MMP-9 and TIMP-1 levels were measured in 147 patients with TBE and 153 controls by ELISA. Serum MMP-9 levels and MMP-9/TIMP-1 ratios of TBE patients were significantly higher than controls (p<0.0001 and p<0.005, respectively). There were no significant differences in serum TIMP-1 levels between TBE patients and controls. Serum MMP-9 and TIMP-1 levels and MMP-9/TIMP-1 ratios were not associated with age of the patients. However, TBE-positive males with TBE had higher levels of MMP-9 than TBE-positive females (p<0.05). Our results suggest that the increased serum level of MMP-9 and MMP-9/TIMP-1 ratio is associated with the pathogenesis of TBE. Serum MMP-9 can serve as an indicator of breakdown of the BBB and inflammatory brain damage during TBE.