Key result
Aortic constriction in rats causes progressive LVH, and early LA diameter predicts late myocardial fibrosis.
Why the study?
The precise disease progression in the O-ring induced ascending aortic constriction rat model had not been thoroughly evaluated, and early imaging biomarkers predicting subsequent myocardial fibrosis were needed.
In a rat model of progressive pressure overload, early left atrial enlargement on CMR predicts subsequent myocardial fibrosis, highlighting its utility for translational research.
No takes yet. Share an insight, caveat, or question.
Supports LA diameter as fibrosis biomarker in rat pressure-overload models; leaves open translation to human monitoring.
Aortic stenosis is a debilitating disease characterized by pressure overload and development of myocardial fibrosis. Animal models that mimic this disease are crucial for translational research. Aortic constriction in rats is commonly used to induce pressure overload, but the precise disease progression in the O-ring induced model of ascending aortic constriction has not been thoroughly evaluated. Additionally, identifying early imaging biomarkers that can predict fibrosis could enhance the model’s translational relevance. This study aims to evaluate a rat model of progressive pressure overload using cardiovascular magnetic resonance imaging (CMR) by investigating the degree of constriction at different time points and identifying early imaging biomarkers predicting myocardial fibrosis at later stages. Sprague Dawley rats (n=14) underwent aortic banding with O-rings (inner diameter of 1.5 mm or 1.3 mm). Sham-operated rats (n=8) served as controls. CMR was performed every fourth week until 20 weeks post-surgery, followed by tissue harvesting and measurements of fibrosis with histology. All banding groups gradually developed left ventricular (LV) hypertrophy, impaired LV diastolic function (increased E/SRe), increased left atrial (LA) size, and impaired LA function (reduced LA ejection fraction and peak LA strain), but preserved LV ejection fraction during the course of study. The tightest constriction exhibited increased LV fibrosis at 20 weeks. LA diameter at 4 weeks independently predicted LV myocardial fibrosis. This animal model mimics the gradual progression of stenosis seen in humans, highlighting its translational potential. Early LA diameter predicted myocardial fibrosis. These findings underscore the model’s relevance for studying disease progression in LV pressure overload. This study evaluated a rat model of progressive pressure overload using O-ring aortic banding with two constriction sizes (1.5 mm and 1.3 mm) in addition to sham-operated controls. Longitudinal magnetic resonance imaging (MRI) assessed the disease development and revealed gradual development of cardiac hypertrophy, impaired left ventricular diastolic function, enlarged left atrial size and reduced left atrial function in the constricted animals. Left atrial diameter at 4 weeks post-surgery was found to be an independent predictor of myocardial fibrosis at later stages.
Hauge‐Iversen et al. (2025) studied Aortic stenosis and progressive pressure overload (n=22). Aortic banding with O-rings vs. Sham operation was evaluated on Degree of constriction at different time points and early imaging biomarkers predicting myocardial fibrosis. O-ring induced ascending aortic constriction in rats caused progressive left ventricular hypertrophy, and left atrial diameter at 4 weeks independently predicted myocardial fibrosis at 20 weeks.
Synapse has enriched 5 closely related papers on similar clinical questions. Consider them for comparative context: