Hypercoagulable State. Hypercoagulable TMPro/Pro:ApoE−/− mice – a new mouse model of atherosclerotic plaque vulnerability.Here we present a new hypercoagulable atherosclerosis model, which closely mimics the composition and events leading to plaque destabilization, as normally observed in human atherothrombosis. In a series of sections, demonstrating carotid atherosclerotic plaques, obtained from TMPro/Pro:ApoE−/− mice at 6 weeks after collar placement on high-fat diet regimen, we show multiple signs of plaque vulnerability. (A) A non-occlusive but rapidly progressing atherosclerotic lesion, characterized by abundant infiltration of leukocytes. (B) TMPro/Pro:ApoE−/− mice plaques tend to rupture and dissect (upper arrow) even during the non-occlusive phase, accompanied by “silent” intraluminal thrombosis (lower arrows). Despite the detrimental pathologic characteristics of those lesions, these data confirm the hypothesis that arterial thrombosis might exist long before a fatal event takes place. This is further consolidated by the presence of so called “buried fibrous caps” (indicated by the arrows) in TMPro/Pro:ApoE−/− mice plaques [55], considered a marker of healed plaque ruptures, and also observed in human atherosclerosis. Blue color denotes a massive intraplaque hemorrhage (iron ions deposition) (C). Hypercoagulability induces a severe inflammatory and pro-necrotic intraplaque environment, leading to the formation of enormous necrotic core, thin fibrous caps, further plaque destabilization (D) and atherothrombosis (occlusive intraluminal thrombosis/abundant fibrin(ogen) deposition (indicated by the arrows)) (E). Thrombi undergo fibrotic organization involving vascular smooth muscle cells and fibroblasts ingrowth, and are then partially recanalized by newly formed vessels (arrows, blue color – iron deposition/presence of erythrocytes)(F). Genetic and pharmacological modifications of thrombin formation in apolipoprotein e-deficient mice determine atherosclerosis severity and atherothrombosis onset in a neutrophil-dependent manner. Borissoff JI, Otten JJ, Heeneman S, Leenders P, van Oerle R, Soehnlein O, Loubele ST, Hamulyák K, Hackeng TM, Daemen MJ, Degen JL, Weiler H, Esmon CT, van Ryn J, Biessen EA, Spronk HM, ten Cate H - PloS one (2013). Not Altered. CC.