title: Tissue plasminogen activator (t-PA) promotes neutrophil degranulation and MMP-9 release.
abstract: Recombinant tissue plasminogen activator (t-PA), the only approved stroke treatment, is used for clot lysis within the occluded brain artery. Unfortunately, matrix metalloproteinase-9 (MMP-9) concentration increases after t-PA treatment and has been related to hemorrhagic transformation after ischemic stroke. Although the exact cellular source of brain MMP-9 remains unknown, invading, inflammatory cells, such as neutrophils, release MMP-9 to cross the blood brain barrier. Therefore, we hypothesize that the most feared side effect of stroke reperfusion therapy, brain hemorrhage, is related to t-PA-induced MMP-9 release by neutrophils. We show by means of ELISA that t-PA treatment promotes MMP-9, MMP-8, and tissue inhibitor metalloproteinase-2 release from human neutrophils ex vivo within 10 and 30 min. Moreover, by zymography and Western blot, we observed that neutrophils are emptied of MMP-9 content after t-PA treatment at those times. Finally, total internal reflection fluorescent imaging allowed us to observe the t-PA effect on neutrophils, showing the promotion of degranulation on these cells in vivo. Our data suggest that neutrophils are good candidates to be the main source of MMP-9 following t-PA stroke treatment and in consequence, partially responsible for thrombolysis-related brain bleedings.
authors.affiliation: Neurovascular Research Laboratory, Neurovascular Unit, Department of Neurology, Universitat Autònoma de Barcelona, Institut de Recerca, Hospital Vall d'Hebron, Pg Vall d'Hebron 119-129, 08035 Barcelona, Spain.
authors.forename: Eloy
authors.initials: E
authors.lastname: Cuadrado
authors.forename: Laura
authors.initials: L
authors.lastname: Ortega
authors.forename: Mar
authors.initials: M
authors.lastname: Hernández-Guillamon
authors.forename: Anna
authors.initials: A
authors.lastname: Penalba
authors.forename: Israel
authors.initials: I
authors.lastname: Fernández-Cadenas
authors.forename: Anna
authors.initials: A
authors.lastname: Rosell
authors.forename: Joan
authors.initials: J
authors.lastname: Montaner
mesh_terms: D000328:Adult; D016923:Cell Death / Q000187:drug effects; D015550:Cell Degranulation / Q000187:drug effects*; D002462:Cell Membrane / Q000187:drug effects / Q000378:metabolism; D005260:Female; D006801:Humans; D008297:Male; D020784:Matrix Metalloproteinase 8 / Q000378:metabolism; D020780:Matrix Metalloproteinase 9 / Q000378:metabolism*; D008856:Microscopy, Fluorescence; D009240:N-Formylmethionine Leucyl-Phenylalanine / Q000494:pharmacology; D018375:Neutrophil Activation / Q000187:drug effects; D009504:Neutrophils / Q000187:drug effects / Q000201:enzymology* / Q000378:metabolism / Q000502:physiology*; D019716:Tissue Inhibitor of Metalloproteinase-2 / Q000378:metabolism; D010959:Tissue Plasminogen Activator / Q000494:pharmacology*
chemical_list: D019716:Tissue Inhibitor of Metalloproteinase-2; D009240:N-Formylmethionine Leucyl-Phenylalanine; D010959:Tissue Plasminogen Activator; D020784:Matrix Metalloproteinase 8; D020780:Matrix Metalloproteinase 9