A rat model of dilated cardiomyopathy to investigate partial left ventriculectomy

Rodent Models of Dilated Cardiomyopathy and Heart Failure for Translational Investigations and Therapeutic Discovery

Even with modern therapy, patients with heart failure only have a 50% five-year survival rate. To improve the development of new therapeutic strategies, preclinical models of disease are needed to properly emulate the human condition. Determining the most appropriate model represents the first key step for reliable and translatable experimental research. Rodent models of heart failure provide a strategic compromise between human in vivo similarity and the ability to perform a larger number of experiments and explore many therapeutic candidates. We herein review the currently available rodent models of heart failure, summarizing their physiopathological basis, the timeline of the development of ventricular failure, and their specific clinical features. In order to facilitate the future planning of investigations in the field of heart failure, a detailed overview of the advantages and possible drawbacks of each model is provided.

Quantitative FDG-uptake by positron emission tomography in progressive hypertrophy of rat hearts in vivo

BACKGROUND

Quantitative myocardial fluorodeoxyglucose positron emission tomography (FDG-PET) for assessing glucose uptake in vivo is reliable in normal rat heart.

OBJECTIVE

To assess the applicability of myocardial FDG-PET on multiple occasions in the longitudinal disease process of progressive hypertrophy of rat heart.

METHODS

Six salt-sensitive Dahl rats (Dahl-S) developing progressive hypertrophy with subsequent dilated cardiomyopathy were compared with salt-resistant Dahl rats (controls). FDG-PET was applied twice at early stage (ES: 14-18 weeks) and at late stage (LS: 22-26 weeks) of hypertrophy. Standardized uptake value (SUV) was calculated for comparing between different animal weights and different injection dosages of FDG. For validating the quantitative study, radioactivity of a total of 36 tissue samples was compared with the corresponding PET values.

RESULTS

The left ventricular mass in Dahl-S increased by 17% at ES and by 25% at LS. The SUV in Dahl-S was 95% of controls at ES and reduced to 62% at LS (P=0.023). The heart function started to deteriorate after LS. Linear regression analysis showed a good correlation between the radioactivity of tissue samples and PET values (Y=1.20X, P<0.0001, R2=0.979).

CONCLUSIONS

Small animal PET studies on longitudinal multiple occasions in vivo were feasible and useful for the repeating assessment of glucose uptake. The reduction of glucose uptake in progressive hypertrophy of heart over time may precede its progression to heart failure.

Importance of preserving the apex and plication of the base in left ventricular volume reduction surgery

OBJECTIVE

Volume reduction surgery for dilated cardiomyopathy has not yielded predictable outcomes. The purpose of this study was to clarify the efficacy of modified volume reduction surgery in preserving the left ventricular apex and reducing the left ventricular diameter at the base to maintain fiber continuity.

METHODS

Heart failure was induced with propranolol in 12 dogs, and the animals were randomized into 2 groups. In one group the left ventricular wall was plicated between the 2 papillary muscles from the middle to the apex (apex-sacrificing volume reduction surgery, group A, n = 6), and in the other group plication was done from the base to the middle (apex-sparing volume reduction surgery, group B, n = 6). Left ventricular function was then compared between the groups by using echocardiography and sonomicrometry crystals.

RESULTS

After volume reduction surgery, the fractional area change at the base in group B was greater than that in group A (40% +/- 3% vs 27% +/- 4%, P =.003). Cardiac output in group B was better than that in group A (2.5 +/- 0.2 vs 1.8 +/- 0.2 L/min, P =.023). Left ventricular end-diastolic pressure in group A was higher than that in group B (16 +/- 2 vs 8 +/- 1 mm Hg, P =.001). Fractional shortening in the long axis, as assessed by means of sonomicrometry, was better in group B than in group A.

CONCLUSIONS

Apex-sparing volume reduction surgery capable of maintaining left ventricular fiber continuity provided better left ventricular function in both the systolic and diastolic phases than apex-sacrificing volume reduction surgery in the acute heart failure model. This modification might improve the results of left ventricular volume reduction surgery.

Partial left ventriculectomy: history, current status, and future role

Whereas discouraging clinical results and lack of scientific evidence decreased the initial interest in partial left ventriculectomy (PLV), factors contributing to success and failure have now been identified by clinical observations, theoretical analyses, and data from an international registry, which are herein reviewed to outline the current status and future role of this procedure as a treatment of heart failure.