2019 Volume 1 Issue 5 Pages 199-205
Background:High-frequency ultrasound has facilitated in vivo measurement of murine ascending aorta, allowing aortic strain to be determined from 2-D imaging. Thoracic aortic aneurysms associated with mutations infibrillin-1(FBN1) display elastin fragmentation, which may affect aortic strain. In this study, we determined the relationship between elastin fragmentation and aortic circumferential strain in wild-type (WT) and fibrillin-1 hypomorphic (FBN1mgR/mgR) mice.
Methods and Results:Luminal diameter of the ascending aorta from WT andFBN1mgR/mgRmice was measured in systole and diastole. Expansion of the ascending aorta during systole in male and female WT mice was 0.21±0.02 mm (16.3%) and 0.21±0.01 mm (17.0%), respectively, while expansion in male and femaleFBN1mgR/mgRmice was 0.11±0.04 mm (4.9%) and 0.07±0.02 mm (4.5%), respectively. Reduced circumferential strain was observed inFBN1mgR/mgRmice compared with WT littermates. Elastin fragmentation was inversely correlated to circumferential strain (R2=0.628, P=0.004) and significantly correlated with aortic diameter (systole, R2=0.397, P=0.038; diastole, R2=0.515, P=0.013).
Conclusions:FBN1mgR/mgRmice had increased aortic diameter, reduced circumferential strain, and increased elastin fragmentation. Elastin fragmentation inFBN1mgR/mgRand their WT littermates was correlated with reduced circumferential strain.