Local Anticoagulation via Gene Therapy: Towards Preventing Cardioembolic Stroke

Abstract

Cardiac thromboembolism persists as the culprit behind most ischemic strokes; a majority arising from the left atrial appendage. Oral anticoagulants, while effective in preventing stroke, come with an attendant bleeding risk and are contraindicated in a subset of at-risk patients. To combat this disease and overcome limitations of systemic oral anticoagulants, we aimed to develop a novel anticoagulant viral vector to focally target cardiac regions of increased thrombotic potential, thereby presenting an alternative therapy for long-term anticoagulation.

The anticoagulant phenotype of these vectors was functionally assessed through in vitro and ex vivo platforms. For in vitro testing, a novel, cell-based version of the calibrated automated thrombogram assay was utilised to determine thrombokinetics and thrombogenic potential. For ex vivo testing, freshly isolated and characterized porcine left atrial appendage endothelial cells were used to coat microfluidic devices. Cells were injured with TNF-α prior human, whole blood, perfusion and changes in fibrin, platelets and neutrophils were investigated.

Experimental findings in vitro demonstrated a significant decrease in the endogenous thrombin potential of vector-transduced cells, coupled with a significant decrease in the velocity of thrombogenesis. Furthermore, transduced cells had a marked decrease in the peak rate of thrombin generation and a significant increase in the time taken to achieve peak thrombin generation. Experimental findings from ex vivo work highlighted significant reductions in fibrin and platelets following anticoagulant vector transduction, as well as notable decreases in the neutrophil population.

These findings demonstrate the antithrombotic, antiplatelet and anti-inflammatory effect of our vectors in inhibiting thrombosis. Thereby, these findings help to guide the development of focal gene therapy strategies to target thrombosis at its point of origin, in the prevention of cardioembolic stroke.