Key result
In a novel conscious rat model of ischemic cardiomyopathy, the percent increase in left ventricular diastolic area on day 3 significantly predicted left ventricular dilation at week 4 (r=0.91, p<0.0001).
Effect estimate: r=0.91
p-value: p=<0.0001
A novel conscious rat model of repetitive ischemia/reperfusion successfully induces ischemic cardiomyopathy, with early LV dilatory response predicting long-term severity.
Early LV dilation may predict remodeling in rat ischemic cardiomyopathy models; hypothesis-generating and leaves open clinical translation.
BACKGROUND: A rodent model of ischemic cardiomyopathy (ICM) induced by repetitive brief ischemia/reperfusion (I/R) injury while conscious has not been previously established. METHODS AND RESULTS: A newly developed coronary occluder was implanted in male Wistar rats. A repetitive I/R protocol (20 s, 2 min, followed by main 30 min--ischemia, every 48 h, for 4 weeks) was introduced while the animals were conscious. The I/R protocol did not induce transmural scar formation but induced (1) residual myocytes with scattered infiltration of fibrosis (Masson trichrome stain), (2) coronary hypoperfusion ((201)Tl-Cl autoradiogram), (3) reduced coronary microvascular volume fraction (microCT), and (4) gradually progressive left ventricular (LV) dilation (echocardiography). These parameters of ICM showed interindividual variation; however, the percent increase in LV diastolic area on day 3 was significantly correlated with LV dilation (r=0.91, p<0.0001), fibrosis (r=0.77, p=0.0034), and reduction in microvessels (r=0.67, p=0.040) at week 4. The LV dilatory response on day 3 also correlated with inducible nitric oxide synthase expression (immunohistochemistry, day 3) in the LV (r=0.92, p=0.028). CONCLUSIONS: A novel rat model of ICM induced by repetitive I/R while conscious showed interindividual variation in the severity of ICM in the advanced stage, but this was predictable non-invasively (by LV dilatory response) during the initial stage of repetitive I/R.
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Toyota et al. (2007) studied Ischemic cardiomyopathy (n=22). Repetitive ischemia/reperfusion (I/R) protocol vs. Baseline was evaluated on Correlation between percent increase in LV diastolic area on day 3 and LV dilation at week 4 (r=0.91, p=<0.0001). In a novel conscious rat model of ischemic cardiomyopathy, the percent increase in left ventricular diastolic area on day 3 significantly predicted left ventricular dilation at week 4 (r=0.91, p<0.0001).
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