2006 Volume 29 Issue 2 Pages 57-61
Recent studies have been shown that levels of matrix metalloproteinase-9 (MMP-9) increase after traumatic brain injury (TBI), degrading components of the basal lamina disrupting the blood-brain barrier. We measured the concentration of MMP-9, tissue inhibitor of matrix metalloproteinase-1 (TIMP-1), and interleukin-6 (IL-6) in blood after TBI. Samples were collected from systemic arterial and jugular venous blood from seven patients with severe TBI on days 0 and 1 post-injury. All patients underwent hypothermia as soon as possible after admission. Before induction of hypothermia, level of MMP-9 exceeded the normal range, however, level of TIMP-1 was below the normal range. On day 1, MMP-9 levels in arterial blood and internal jugular venous blood decreased significantly, to within the normal range. In addition to these changes, a significant correlation was seen between levels of MMP-9 and IL-6 in internal jugular venous blood during the investigation period. These results indicate that imbalance between MMP-9 and TIMP-1 may contributes to the pathophysiology of TBI. MMP-9 is induced by inflammatory events following TBI. Hypothermia may suppress the elevation of MMP-9 with suppression of the inflammatory response.
