Abstract 10292: Deep Vein Thrombosis in Mice After Endothelial Denudation Critically Depends On P2y12-Receptor Signaling - Lessons From a Novel Contrast Ultrasound Technique
Introduction. Deep vein thrombosis (DVT) is often triggered by endothelial injury and can culminate in pulmonary embolism. Ultrasound is the gold standard diagnostic tool to detect and quantify DVT in patients. To date, ultrasound techniques have not been established in murine models of DVT, since fresh thrombi are small and iso-echogenic in mice. Here, we examined the feasibility of real-time contrast-enhanced ultrasound (CEUS) to visualize growing inferior vena cava (IVC) thrombosis. Furthermore, our aim was to assess IVC thrombus development in P2Y12 knockout mice (P2Y12-/-) to point out the important role of the P2Y12 receptor regarding platelet activation.
Methods. The distal IVC was exposed by median laparotomy and incubated with a filter paper saturated with 10% ferric chloride for 5 minutes to induce non-occlusive thrombosis in male C57Bl/6 mice after treatment with enoxaparin (n=8) or saline (n=16) and in P2Y12-/- (n=6). In sham-operated animals, the filter paper contained saline. Thrombi were weighed and assessed in immuno-histochemistry. Incorporation platelets into growing thrombi was assessed by intravital microscopy. Ultrasound microbubbles were injected intravenously and contrast intensities were continuously monitored with a 13MHz ultrasound transducer.
Results. Treatment with ferric chloride resulted in platelet-rich thrombus growth in saline-treated mice. Sham-operated mice, enoxaparin-treated wild-type mice and P2Y12-/- developed significantly smaller thrombi (p<0.05). CEUS showed rapid contrast wash-in with uniform contrast enhancement throughout the IVC lumen. Growing thrombi delineated clearly as negative contrast. Thrombus size in CEUS was significantly smaller in enoxaparin-treated mice and P2Y12-/- as compared to saline-treated wild-type mice (0.314±0.08mm2 versus 0.03±0.07 mm² versus 0.796±0.11mm2 in the maximal sagittal plane, p<0.05).
Summary. We established a new mouse model for real-time quantification of growing DVT by CEUS. Thrombus size in CEUS correlated well with histology and intravital microscopy results. Interestingly, P2Y12-/- showed reduced thrombus growth in this model, indicating an important role of the P2Y12 receptor in ferric chloride-induced deep vein thrombosis.
- © 2011 by American Heart Association, Inc.