MMP9 variation after thrombolysis is associated with hemorrhagic transformation of lesion and death

Experimentally, matrix metalloproteinases (MMPs) play a detrimental role related to hemorrhagic transformation and severity of an ischemic brain lesion. Tissue-type plasminogen activator (tPA) enhances such effects. This study aimed to expand clinical evidence in this connection. METHODS: We measured MMPs 1, 2, 3, 7, 8, 9, and tissue inhibitors of metalloproteinases 1, 2, 4 circulating level in blood taken before and 24 hours after tPA from 327 patients (mean age, 68.9±12.1 years; median National Institutes of Health Stroke Scale, 11) with acute ischemic stroke. Delta median values ([24 hours post tPA-pre tPA]/pre tPA) of each MMP or tissue inhibitors of metalloproteinase were analyzed across subgroups of patients undergoing symptomatic intracerebral hemorrhage, 3-month death, or 3-month modified Rankin Scale score 3 to 6. RESULTS: Adjusting for major clinical determinants, only matrix metalloproteinase-9 variation proved independently associated with death (odds ratio [95% confidence interval], 1.58 [1.11-2.26]; P=0.045) or symptomatic intracerebral hemorrhage (odds ratio [95% confidence interval], 1.40 [1.02-1.92]; P=0.049). Both matrix metalloproteinase-9 and tissue inhibitors of metalloproteinase-4 changes were correlated with baseline, 24 hours, and 7 days National Institutes of Health Stroke Scale (Spearman P from <0.001 to 0.040). CONCLUSIONS: Our clinical evidence corroborates the detrimental role of matrix metalloproteinase-9 during ischemic stroke treated with thrombolysis, and prompts clinical trials testing agents antagonizing its effects.