Serial high resolution 3D–MRI after aortic banding in mice: band internalization is a source of variability in the hypertrophic response
Author(s)
A. Lygate, Craig
E. Schneider, Jürgen
Hulbert, Karen
Hove, Michiel ten
M. Sebag-Montefiore, Liam
J. Cassidy, Paul
Clarke, Kieran
Neubauer, Stefan
Griffith University Author(s)
Year published
2006
Metadata
Show full item recordAbstract
Transverse aortic constriction (TAC) is used as a model of left ventricular hypertrophy and failure; however, there is extensive variability in the hypertrophic response. In 43 mice that underwent TAC with a 7-0 polypropylene suture, 13 were identified by echocardiography with initial LV hypertrophy that halted or regressed over time. Post-mortem examination on 7 of these mice found the constricting band to be intact, but partially internalized into the aortic lumen, allowing blood flow around the stenosis. To confirm this prospectively in vivo we then followed 12 mice after TAC for 6 weeks, using a new high resolution ...
View more >Transverse aortic constriction (TAC) is used as a model of left ventricular hypertrophy and failure; however, there is extensive variability in the hypertrophic response. In 43 mice that underwent TAC with a 7-0 polypropylene suture, 13 were identified by echocardiography with initial LV hypertrophy that halted or regressed over time. Post-mortem examination on 7 of these mice found the constricting band to be intact, but partially internalized into the aortic lumen, allowing blood flow around the stenosis. To confirm this prospectively in vivo we then followed 12 mice after TAC for 6 weeks, using a new high resolution 3D-MRI method to measure minimal aortic arch cross-sectional area (CSA). Three of the 12 mice developed a significantly increased aortic CSA (0.31 ᠰ.15 on day 2 vs. 1.11 ᠰ.29 mm2 on day 42; P < 0.05), which was independently confirmed by dissection. These mice had internalized part of the band within the aortic lumen and, by week 6, showed significantly less LV hypertrophy and better systolic function. Nine of the 12 mice showed no change in aortic CSA. Band internalization could be prevented when two banding sutures were placed side-by-side (n = 10). This is the first observation that a significant subset of animals following TAC bypass the stenosis resulting in partial regression of hypertrophy.
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View more >Transverse aortic constriction (TAC) is used as a model of left ventricular hypertrophy and failure; however, there is extensive variability in the hypertrophic response. In 43 mice that underwent TAC with a 7-0 polypropylene suture, 13 were identified by echocardiography with initial LV hypertrophy that halted or regressed over time. Post-mortem examination on 7 of these mice found the constricting band to be intact, but partially internalized into the aortic lumen, allowing blood flow around the stenosis. To confirm this prospectively in vivo we then followed 12 mice after TAC for 6 weeks, using a new high resolution 3D-MRI method to measure minimal aortic arch cross-sectional area (CSA). Three of the 12 mice developed a significantly increased aortic CSA (0.31 ᠰ.15 on day 2 vs. 1.11 ᠰ.29 mm2 on day 42; P < 0.05), which was independently confirmed by dissection. These mice had internalized part of the band within the aortic lumen and, by week 6, showed significantly less LV hypertrophy and better systolic function. Nine of the 12 mice showed no change in aortic CSA. Band internalization could be prevented when two banding sutures were placed side-by-side (n = 10). This is the first observation that a significant subset of animals following TAC bypass the stenosis resulting in partial regression of hypertrophy.
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Journal Title
Basic Research in Cardiology
Volume
101
Issue
1
Subject
Medical Physics
Cardiorespiratory Medicine and Haematology