Abstract
Preclinical studies of animals with risk factors, and how those risk factors contribute to the development of cardiovascular disease and cardiac dysfunction, are clearly needed. One such approach is to feed mice a diet rich in fat (i.e. 60%). Here, we determined whether a high fat diet was sufficient to induce cardiac dysfunction in mice. We subjected mice to two different high fat diets (lard or milk as fat source) and followed them for over six months and found no significant decrement in cardiac function (via echocardiography), despite robust adiposity and impaired glucose disposal. We next determined whether antecedent and concomitant exposure to high fat diet (lard) altered the murine heart’s response to infarct-induced heart failure; high fat feeding during, or before and during, heart failure did not significantly exacerbate cardiac dysfunction. Given the lack of a robust effect on cardiac dysfunction with high fat feeding, we then examined a commonly used mouse model of overt diabetes, hyperglycemia, and obesity (db/db mice). db/db mice (or STZ treated wild-type mice) subjected to pressure overload exhibited no significant exacerbation of cardiac dysfunction; however, ischemia-reperfusion injury significantly depressed cardiac function in db/db mice compared to their non-diabetic littermates. Thus, we were able to document a negative influence of a risk factor in a relevant cardiovascular disease model; however, this did not involve exposure to a high fat diet. High fat diet, obesity, or hyperglycemia does not necessarily induce cardiac dysfunction in mice. Although many investigators use such diabetes/obesity models to understand cardiac defects related to risk factors, this study, along with those from several other groups, serves as a cautionary note regarding the use of murine models of diabetes and obesity in the context of heart failure.
Highlights
Heart disease is the leading cause of death in the United States
We investigated whether long-term feeding of high fat diet alone in naïve mice can cause cardiac dysfunction
After 28 weeks, both the HFDM and HFDL mice weighed significantly more than the low fat diet (LFD) group (51.6±0.5 g and 51.9±0.4 g, vs. 34.3±1.0 g, respectively, p0.05 vs. LFD) and Dexascan analysis showed that the percent fat mass was significantly increased and lean mass was significantly reduced in both the HFDM and HFDL compared to LFD fed mice (Figure 1D-E)
Summary
Heart disease is the leading cause of death in the United States. Over one half of the United States population will be obese by the year 2020. Obesity and diabetes are prominent risk factors for development of heart disease and in order to determine the role these risk factors play in heart disease, various animal models have been employed to recapitulate essential elements of these risk factors. Given the ubiquity of genetically modified mice, many investigators have used diabetic/high-fat fed mouse models to attempt to answer important questions about cardiovascular disease. Some of the most prominent models include leptin receptor deficiency (db/ db), streptozotocin treatment, and high fat diet-induced obesity, all of which were used in the present study
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