Dual Antiplatelet Therapy Increases Hemorrhagic Transformation Following Thrombolytic Treatment in Experimental Stroke

Abstract

Background and Purpose— Dual antiplatelet treatment poses a risk for increased hemorrhagic transformation (HT) following intravenous thrombolysis and mechanical thrombectomy. The aim of this study was to implement a model of experimental stroke with tissue-type plasminogen activator (tPA)-associated HT in mice on dual antiplatelet treatment to enable mechanistic studies and also to allow for an initial assessment of therapeutic approaches to limit HT. Methods— Male C57BL6 mice were fed with Aspirin and Clopidogrel via drinking water for 3 days. Subsequently, mice were subjected to 2-hour transient middle cerebral artery occlusion, and tPA was infused when indicated. HT was quantified by measuring hemorrhaged areas in brain sections with ImageJ. TTC staining was used to determine infarct size. Platelet function was tested in vitro using flow cytometry and in vivo with standard tail bleeding tests. Results— Both flow cytometry and tail bleeding volumes indicated significantly reduced platelet function following Aspirin and Clopidogrel treatment. While tPA administered 2 hours after onset of middle cerebral artery occlusion did not cause bleeding in control mice (0.51±0.13 mm2), HT significantly increased by 18.9±5.4 mm2 ( P =0.0045) in Aspirin and Clopidogrel mice treated with tPA. HT in aspirin and clopidogrel mice not treated with tPA was nonsignificantly elevated by 8.0±4.6 mm 2 ( P =0.3784) compared with controls. Infarct sizes did not differ between groups. The HT persisted when the tPA dosage was reduced. Conclusions— We successfully established a translational stroke model of tPA treatment under dual antiplatelet treatment. The impaired platelet function led to an increased risk for HT in tPA-treated mice. Reducing the dosage of tPA did not prevent this hemorrhagic complication.

Predicting Factors of Functional Outcome in Patients with Acute Ischemic Stroke Admitted to Neuro-Intensive Care Unit—A Prospective Cohort Study

“…Conversely, it has been reported that previous treatment with aspirin monotherapy increases the bleeding risk of rt-PA in both observational and randomized trials with no effect on clinical outcome and the risk of intracerebral hemorrhage is increased with the combination of aspirin and clopidogrel [45]. Moreover, in an experimental model of stroke, Zheng et al demonstrated that mice pretreated with dual antiplatelet therapy showed an increased risk of hemorrhagic transformation when treated with tPA [46]. These results may suggest a cautious use of anticoagulant drugs in the acute stage, avoiding the unnecessary combination of antithrombotic treatments.…”

Dental pulp stem cell‐derived exosomes alleviate cerebral ischaemia‐reperfusion injury through suppressing inflammatory response

“…Brain infarct size was assessed using a 2,3,5‐triphenyltetrazolium chloride staining (TTC; Sigma‐Aldrich) 36 . On day 7, 6 mice/group were sacrificed.…”

“…Brain infarct size was assessed using a 2,3,5‐triphenyltetrazolium chloride staining (TTC; Sigma‐Aldrich). 36 On day 7, 6 mice/group were sacrificed. Mouse brain was dissected and frozen at −80°C for 10 minutes and sectioned into 2‐mm‐thick slices coronally.…”

Measurement of Platelet Function in an Experimental Stroke Model With Aspirin and Clopidogrel Treatment

“…HT was assessed as red areas in brain sections, outlined and measured using ImageJ. Hemorrhages were classified according to the ECASS II morphologic definitions (24,25) adapted to animal models as used in previous publications (12,26,27). Therefore, every section was individually scored on a 5 point ordinal scale (1 = no HT; 2 = hemorrhagic infarction type 1; 3 = hemorrhagic infarction type 2; 4 = parenchymal hemorrhage type 1; 5 = parenchymal hemorrhage type 2) and an overall grade for every brain was determined according to the highest grade occurring among the sections.…”

“…To address this gap of knowledge, we recently established a model of tPA-associated hemorrhagic transformation (HT) in mice pretreated with Aspirin and Clopidogrel [ASA+CPG, (12)]. While establishing antiplatelets in rodents, the individual hemostatic status of the single mouse becomes relevant.…”