Role of the MMP9 Gene in Hemorrhagic Transformations After Tissue-Type Plasminogen Activator Treatment in Stroke Patients

Background and Purpose—Despite the benefits of tissue-type plasminogen activator treatment, some stroke patients experience adverse hemorrhagic transformations (HT). Plasma protein levels of MMP9 have been associated with HT occurrence. We aimed to analyze the association of the MMP9 gene with HT occurrence. Methods—We analyzed the MMP9 gene in blood samples from 885 stroke patients treated with tissue-type plasminogen activator by tag-SNP, imputed SNP, direct sequencing, and RNA expression. Results—We did not observe any significant association between MMP9 genetic variations or MMP9 expression and HT occurrence. Moreover, no association was found between MMP9 expression and MMP9 polymorphisms. Conclusions—Genetic variations in the MMP9 gene are not associated with HT occurrence in tissue-type plasminogen activator-treated patients.