Abstract
BackgroundCardiac lipomatous metaplasia (LM) occurs in patients with chronic ischemic heart disease and heart failure with unclear mechanisms. We studied coronary occlusion/reperfusion-induced myocardial infarction (MI) in rabbits during a 9-months follow-up using 3.0 T magnetic resonance scanner, and confirmed the presence of MI in acute phase and LM in chronic phase using histopathology.MethodsMI was surgically induced in 10 rabbits by 90-min coronary artery occlusion and reperfusion. Forty-eight hours later, multiparametric cardiac magnetic resonance imaging (cMRI) was performed at a 3.0 T clinical scanner for MI diagnosis and cardiac function analysis. Afterwards, seven rabbits were scarified for histochemical staining with triphenyltetrazolium chloride (TTC), and hematoxylin-eosin (HE), and 3 were scanned with cMRI at 2 days, 2 weeks, 2 months and 9 months for longitudinal observations of morphological and functional changes, and the fate of the animals. Post-mortem TTC, HE and Masson's trichrome (MTC) were studied for chronic stage of MI.ResultsThe size of acute MI correlated well between cMRI and TTC staining (r2=0.83). Global cardiac morphology-function analysis showed significant correlation between increasing acute MI size and decreasing ejection fraction (p<0.001). During 9 months, cMRI documented evolving morphological and functional changes from acute MI to chronic scar transformation and fat deposition with a definite diagnosis of LM established by histopathology.ConclusionsAcute MI and chronic LM were induced in rabbits and monitored with 3.0 T MRI. Studies on this platform may help investigate the mechanisms and therapeutic interventions for LM.
Highlights
Cardiac lipomatous metaplasia (LM) occurs in patients with chronic ischemic heart disease and heart failure with unclear mechanisms
Its versatile advantages have been demonstrated in cardiac magnetic resonance imaging studies at a 1.5 T clinic magnet [2]. 3.0 T MRI scanner with 8-channels or more cardiac array coils can obtain cardiac images with higher signal-to -noise-ratio, temporal and spatial resolutions, and shorter acquisition time compared to the conventional 1.5 MRI
A leftside thoracotomy was performed at the fourth intercostal space and a suture was placed underneath the left coronary artery
Summary
Cardiac lipomatous metaplasia (LM) occurs in patients with chronic ischemic heart disease and heart failure with unclear mechanisms. The moderate size rabbit model of occlusion/reperfusioninduced myocardial infarction (MI) has been used in cardiac imaging research [1,2,3]. Myofibroblasts are supposed to play an important role in myocardial healing after MI These cells produce collagen to constitute scar tissue, prevent infarct expansion, and stabilize ventricular wall of the heart [7]. Cardiac lipomatous metaplasia (LM) refers to the adipose tissue present in the cardiac wall to replace scar tissue within an infarcted territory. One clinical report showed that the LM occurred more often in hyperlipoproteinaemia patients and in 11% patients with chronic ischemic heart disease (CIHD) [8]. Findings of LM have been seldom described in veterinary subjects [10], yet never established by both in vivo and ex vivo animal research
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
