MMP9 and acute myocardial infarction: Besides, the results of the present study provide two novel findings: (1) tPA upregulated the expressions of proangiogenic factors only in the presence of MMP-9 under ischemic condition; (2) tPA therapy may be beneficial for patients with acute myocardial infarction and acute ischemic stroke other than its role in enhancing reperfusion through the mechanism of thrombolysis.