Abstract TMP116: A Novel Microfluidic Model Of Ischemic Stroke Recapitulating Arterial Occlusion And Prolonged Retraction

Abstract

To our knowledge, an ex vivo model of thrombotic occlusion that (1) mimics arterial setting, (2) allows true occlusion, and (3) drug delivery without disturbing the thrombus does not exist. A platform with these capabilities would allow for high-throughput mechanistic study of thrombosis and thrombolysis. Here we present a microfluidic system that achieves these goals, providing a biofidelic ex vivo platform to study ischemic stroke. A mold with an upstream Y and a region of stenosis was fabricated and used to manufacture microfluidic chambers. Channels were coated with collagen at the stenosis. Heparinized blood was collected from healthy human donors (N=3) and platelets were labelled with fluorescent anti-CD41. Samples were perfused at 10000/s and outflow mass collected on a scale. Occlusion was indicated by mass plateau, and thrombi were left to retract in situ for 0 or 6 hrs. Kinetic immunofluorescent images were captured and used to derive surface area and the image profile by averaging MFI in each pixel column. Sample from the same donor dosed with 0.7 or 7nM alteplase (ALT) was perfused using the Y inlet using a constant pressure head (1000/s; mimicking middle cerebral artery) for 120 min. After 6 hours of post-occlusion retraction, thrombi substantially remodeled. The MFI curves (Fig 1) demonstrate even distribution of MFI post-occlusion that shifts to a central peak after 6 hr. Dosed sample from the same donor was able to be delivered upstream of the thrombus without disruption. Immediate reperfusion resulted in a reduction in thrombus surface area of (mean (SD)) 2% (10%) with 0.7nM ALT, 23% (7%) with 7nM, and 15% (1%) with vehicle. Reperfusion after 6 hrs resulted in a reduction of 14% (14%) with 0.7nM, 45% (12%) with 7nM, and 17% (8%) with vehicle. We have established an ex vivo high throughput system capable of recapitulating arterial occlusion, thrombus retraction in situ , drug delivery, and thrombolysis. This system can be used for mechanistic inquiry and drug discovery.