Carboxypeptidase U (TAFIa) decreases the efficacy of thrombolytic therapy in ischemic stroke patients

Abstract

Introduction Thrombolytic therapy improves clinical outcome in patients with acute ischemic stroke but is compromised by symptomatic intracranial hemorrhage and an unpredictable therapeutic response. In vitro and in vivo data suggest that activation of procarboxypeptidase U (proCPU) inhibits fibrinolysis. Aims To investigate whether the extent of proCPU activation is related to efficacy and safety of thrombolytic therapy in ischemic stroke patients. Methods In twelve patients with ischemic stroke who were treated with intravenous ( n = 7) or intra-arterial ( n = 5) thrombolysis, venous blood samples were taken at different time points before, during and after thrombolytic therapy. ProCPU and carboxypeptidase U (CPU, TAFIa) plasma concentrations were determined by HPLC. The maximal CPU activity (CPU max) and the percentage of proCPU consumption during thrombolytic therapy were calculated. The efficacy and safety of the thrombolytic therapy were assessed by evolution of the clinical deficit, recanalisation, final infarct volume, thrombolysis-induced intracranial hemorrhage and mortality. Results No correlations between CPU max or proCPU consumption and patient or stroke characteristics were found. However, CPU max is associated with evolution of the clinical deficit and achieved recanalisation. ProCPU consumption is related to the risk of intracranial hemorrhage, mortality and final infarct volume. Conclusions Irrespective of patient and stroke characteristics, CPU max and proCPU consumption during thrombolytic treatment for ischemic stroke are parameters for therapeutic efficacy and safety. Further evaluation of the clinical applicability of these parameters and further investigation of the potential role for CPU inhibitors as adjunctive therapeutics during thrombolytic treatment may be of value.