Elastin fragmentation in atherosclerotic mice leads to intraplaque neovascularization, plaque rupture, myocardial infarction, stroke, and sudden death

Abstract

Aims There is a need for animal models of plaque rupture. We previously reported that elastin fragmentation, due to a mutation (C1039G+/-) in the fibrillin-1 (Fbn1) gene, promotes atherogenesis and a highly unstable plaque phenotype in apolipoprotein E deficient (ApoE-/-) mice on a Western-type diet (WD). Here, we investigated whether plaque rupture occurred in ApoE-/-Fbn1C1039G+/- mice and was associated with myocardial infarction, stroke, and sudden death. Methods and results Female ApoE-/-Fbn1C1039G+/- and ApoE-/- mice were fed a WD for up to 35 weeks. Compared to ApoE-/- mice, plaques of ApoE-/-Fbn1C1039G+/- mice showed a threefold increase in necrotic core size, augmented T-cell infiltration, a decreased collagen I content (70 ± 10%), extensive neovascularization, intraplaque haemorrhage, and a significant increase in matrix metalloproteinase-2, -9, -12, and -13 expression or activity. Plaque rupture was observed in 70% of ascending aortas and in 50% of brachiocephalic arteries of ApoE-/-Fbn1C1039G+/- mice. In ApoE-/- mice, plaque rupture was not seen in ascending aortas and only in 10% of brachiocephalic arteries. Seventy percent of ApoE-/-Fbn1C1039G+/- mice died suddenly, whereas all ApoE-/- mice survived. ApoE-/-Fbn1C1039G+/- mice showed coronary plaques and myocardial infarction (75% of mice). Furthermore, they displayed head tilt, disorientation, and motor disturbances (66% of cases), disturbed cerebral blood flow (73% of cases; MR angiograms) and brain hypoxia (64% of cases), indicative of stroke. Conclusions Elastin fragmentation plays a key role in plaque destabilization and rupture. ApoE-/-Fbn1C1039G+/- mice represent a unique model of acute plaque rupture with human-like complications.